JPS58122709A - Foil wound transformer - Google Patents

Abstract

PURPOSE:To uniform a rise in temperature in windings by supplying hollow rings with refrigerants and by concentrically cooling the upper and the lower parts of a high-voltage winding by a structure wherein a low-voltage winding, the high-voltage winding, and cooling ducts which are provided by required number are wound on an iron core, and a metallic cylinder having the hollow rings at the upper and the lower parts of the metallic cylinder is positioned at the outside of the high-voltage winding. CONSTITUTION:Metallic sheets 2 and insulating sheets 3 are repeatedly wound on an iron core 1 to form a low-voltage winding 4 and a high-voltage winding 5. Cooling ducts 6 having refrigerant paths are positioned among respective windings 4, 5 by required number. Furtheremore, a metallic cylinder 17 is positioned by contacting with the high-voltage winding 5 at the outside circumference side. Hollow rings 16a, 16b are provided at the upper and the lower parts of the cylinder 17. A metallic cylinder 21 having rings is positioned at the outside of the winding 4, if necessary. The hollow rings of the respective cylinder 17 and cylinder 21 are provided at the opposite sides to the windings 4, 5 to circulate refrigerants in the respective rings. Cooling ducts 6 are connected to the connected pipe paths through insulating pipes to uniform a rise in temperature in the windings 4, 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a foil-wound transformer having a foil winding formed by overlapping a metal sheet and an insulating sheet and having a cooling duct built into the winding.

Technical Background of the Invention Foil-wound transformers have a good space factor, so they have the advantage of being smaller and lighter.69. Already several kV several hundred kVA @ [
It has been put into practical use as a relatively low voltage, small capacity transformer, and is widely available on the market.

Recently, in view of its excellent advantages, research has been conducted into applying it to higher voltage and larger capacity transformers, such as 275 kV and 300 MV. Such high voltage
The key to realizing a large-capacity foil-wound transformer is how to improve cooling capacity and provide high insulation capacity to the windings.

Although such high-voltage, large-capacity transformers have not yet been put to practical use, foil-wound transformers, which are already in the research stage and have cooling ducts built into the windings, have excellent insulation properties. One type of heat/tie type is being considered, which directly cools the heat generated from winding loss by feeding a refrigerant into the coil.

Fig. 1 shows a known example of ζO@0. In Fig. 0, the iron core is from one company,
A metal sheet 2 and an insulating sheet 1 are layered on the outside of this iron core 1, and low-voltage windings 4 and high-voltage windings 5 are wound using a known foil winding method, and annular cooling ducts 6 are connected to these windings at appropriate intervals. Make it built-in.

This cooling duct 6 is, for example, almost cylindrical, with a thin gap inside the wall, which is filled with a refrigerant 16 such as -113 or FC75. The heat generated in the winding is removed by the latent heat of vaporization of the refrigerant, and the refrigerant vapor is transferred to the condenser 8 for water cooling I! 9, it is cooled and condensed. A refrigerant circulation cooling circuit is provided in which the refrigerant liquefied by this condensation is sent to the refrigerant tank J4 for storing refrigerant, and is further sent into the 1# line by the -n fr.

Separated from the media.

A collection pipe 1OA is provided on the exit side of the cooling duct 6 to collect refrigerant vapor and send it to the condenser a, and a collection pipe 1 is used to distribute the refrigerant vapor to the cooling duct 6.
0b is made of metal such as stainless steel, but in order to connect it to the cooling duct 6, it is necessary to provide electrical insulation, so insulated pipes 11 & Ilb are used, and a 10% liquid collection pipe and a 10bd tank are used. Take a ground potential such as 12. Cooling duct - Since the cooling duct is wrapped in the winding, it is electrically coupled to the same potential as the part of the winding in the winding section.

The winding insulation is done using insulating oil sealed in a tank or 8
It is insulated with an insulating medium 13 such as F-gas.

In addition, in FIG. 1, the lead wires of the windings that are not directly connected to the present invention, which will be described later, and the bushings that connect them to the outside of the tank are omitted.

In a transformer of this type, the circulation circuit through which the refrigerant flows for cooling and the insulating medium 13 for insulation are completely separated (separated).For this reason, this type of foil-wound transformer In other words, the transformer will be called a Dragon Ballet type flII/b transformer.

As described above, this type of transformer utilizes the latent heat of vaporization of the refrigerant, so it can be expected to have excellent cooling characteristics, making it promising for large-capacity transformers.

However, the great feature of the 4S elliptical winding is that the mechanical force in the axial direction is extremely small. The distribution shown in the figure is 9. This is called fringing, which occurs in normal 1# wire. There is almost no radial spread of the magnetic flux at the upper and lower ends of the winding. This is because the conductor of the foil winding is axially This is because eddy currents are generated in this conductor due to its large width, and the magnetic flux generated by this eddy current cancels out the magnetic flux of the radial component mentioned above.Problems with the background technologyHowever, this is also a foil. In addition to the normal current that flows in the local direction, eddy currents flow through the conductor of the winding, and while it has the advantage of having a small axial mechanical force, due to the eddy current, The current distribution becomes uneven,
It has the disadvantage that the flow is biased toward the upper and lower ends. Figure 3 shows
The current density at one end of the winding is plotted on the vertical axis, and the radial position of the winding is plotted on the horizontal axis, and is expressed as a ratio to the average current density. inside,
When the high-voltage winding is placed outside, the current distribution becomes most uneven in the innermost conductor of the low-voltage winding and the outermost conductor of the high-voltage winding, and the current density at the upper and lower ends becomes high. That is, the foil-wound winding has a drawback that the upper and lower ends of the inside of the inner winding and the outside of the outer winding tend to locally overheat.

Purpose of the Invention Present Invention This invention has been made in view of the above circumstances, and provides a transformer I! that can suppress local overheating of foil-wound windings and equalize the temperature rise within the windings. Summary of the Invention In order to achieve the above object, the present invention provides an iron core, a metal sheet and an insulating sheet stacked on top of each other to create a high pressure winding and a low pressure winding. A cooling duct that is appropriately arranged in each of these windings and has a refrigerant passage, an O pipe line for circulating a refrigerant in these cooling ducts, and an insulated pipe that connects this pipe line and the cooling duct. In the foil-wound transformer, the winding is cooled by supplying a refrigerant to the cooling duct via the pipe to cool the cooling duct, and the outer periphery of the outer 4IL wire and the inner 06- A substantially cylindrical metal body is disposed on at least the former of the inner station sides, and has a conduit formed therein, in contact with the same surface of the winding, and in the vicinity of the side edge of the winding, but not in contact with the skeleton. , this metal body conduit,
The pipe line that circulates the refrigerant in the cooling duct F is insulated/4
The metal body is connected via a wire, and the metal body is cooled to reduce the current density. .

Embodiment of the Invention Hereinafter, an embodiment of the present invention will be described based on the drawings. Since the apparatus is basically the same in structure as shown in FIG. 1, only the different parts will be explained. FIG. 4 is a sectional view of a main part showing an embodiment of the present invention, and numeral 1 in the figure is an iron core. A low voltage winding 4 and a high voltage winding 5 are wound around this iron core 1 from the inside, and each winding is connected to a metal sheet 2 and an insulating S/
-) J are rolled up one on top of the other, and cooling ducts as described above are disposed at appropriate intervals and built-in. On the outside of the high-voltage winding 5, there is provided a cylindrical metal tube 17 which is made of a metal plate and has hollow rings 16m and Iflb at both upper and lower ends, and which can be divided into semicircular shapes for ease of assembly. The upper and lower rings lea and Jab at the end of this metal cylindrical body 11 are connected to upper and lower liquid collection pipes 10 m and 10 (not shown), respectively, and an insulating pipe 11*.
They are connected by Ilb.

The structure of the metal cylindrical body 11 divided into two parts is shown in FIG. 5, and a liquid guide pipe 1a connecting the lower ring Jab and the upper ring 1-1 is attached to the curved side end of the semi-cylindrical metal plate. However, the upper and lower rings Jam and Jmb have openings a4 and f1m&.

1 Rib is attached. The potential of the metal cylindrical body 17 is the potential of the line end connected to the outermost turn of the metal sheet go.

Figure 5(a) is a front view, and Figure 5(a) is a cross-sectional view of the pottery. A pair of such metal cylindrical bodies 11 are combined to form a cylindrical shape.

And a lower liquid collecting pipe 1 (not shown) common to the cooling duct.
Refrigerant xs led from 0k through insulation/f ig 1lbt
B The opening in the lower cylinder Jab of the metal cylinder 11/4
After entering from Ig1rib and going half way around the ring Jab,
The liquid passes through the liquid guide pipe 11 to reach the upper ring 211, and after making a half-circle inside the ζO upper ring 161, it is sent from the outlet /f1c to the above-mentioned insulated pipe 11at-, not shown, to the upper liquid collection pipe JO&. It will be done.

This device with such a configuration has hollow rings Ig* and Jab at the upper and lower ends of the metal cylindrical body 11, and by flowing a refrigerant into these rings, the upper and lower rings Iga and Jab are made of high-pressure winding @
The upper and lower ends of the outer periphery of the s are intensively cooled, and local overheating of these parts, which has been a problem in the past, can be prevented. Moreover, the metal cylinder 11 has upper and lower rings 161°Ja
Note that b acts as an electrostatic shield by relaxing the electric field concentration at the end of the high-voltage winding 5.Also, the metal cylinder 1rld is of a two-piece type, but it can be made as a single piece. However, in the mounted state, it is necessary to provide a gap along the axial direction at one location on the circumference so as not to form a closed path surrounding the core leg.

FIG. 5 shows another embodiment in which a cooling duct is provided at the end of the winding, in which a low-voltage winding 4 and a high-voltage winding 5 of foil-wound winding are wound around the iron core 1 from the inside. Each winding has a built-in cooling duct, and a hollow upper and lower ring 16 m at the upper and lower ends, similar to the configuration shown in Figure 4, is installed on the outside of the high voltage winding 5.
This is the same as in the case of FIG. 4 in which the metal cylinder 11 having the shape b is placed. Furthermore, a metal cylinder 21 having hollow rings 20m and 10k formed at the upper and lower ends is also arranged inside the low-voltage winding 4. The outer peripheral surface of the solid metal cylinder 21 is formed flat, and the low voltage winding 4 is formed by overlapping and winding the metal sheet 2 and the insulating sheet 1 thereon. The upper and lower rings are 10 m long, the upper and lower liquid collecting tubes 10 are respectively the jams mentioned above, and the insulating/ll pipe 1 m long is installed in 10b.

11b. The metal cylinder 21 has gaps in the axial direction at l locations on the circumference, and has upper and lower parts 17.
At least one set of liquid guiding pipes connecting the job 7 and the job 76a are attached. Terminal 9 is electrically connected to terminal KII of the inner conductor of low voltage winding 4.

In this case, the refrigerant 1j sent from the lower liquid collecting pipe 10b, which is common to the cooling pipe 6, through the insulation/diameter "JJ" is not only applied to the lower ring Jmb of the electrostatic shield 11, but also to the lower part of the metal cylinder 21. The cylinder J6bl (is also guided, reaches the cylinder zaaK inside this lower ring jab, goes around it, passes through the insulation Δ Eve JJm, and reaches the upper liquid collecting pipe 10.a.

In this way, not only the metal cylinder 11 outside the high-voltage winding SO, but also the inside of the low-voltage winding 4 have hollow rings 10 m at the upper and lower ends.
A metal cylinder 21 having a diameter 20b is provided, and this metal cylinder 21
By flowing the refrigerant into the upper and lower cylinders 20m and 10b,
These upper and lower rings j#a and job are high and low voltage windings5. - It is possible to intensively cool the upper and lower ends of the outer periphery and the inner periphery, respectively, to prevent local overheating of these parts.

Usually, the winding is wound on a basic insulating tube with sufficient mechanical strength.

The metal cylinder 11 inside the low-voltage winding in this embodiment serves as a basic insulating cylinder, but it can easily be made to have a strength equal to or higher than that of the insulating cylinder.

Furthermore, in terms of insulation between the iron core 1 and the inner terminal of the low voltage winding 4, it is needless to say that there is no need to maintain a safe distance if the inner terminal of the low voltage winding 4 serves as the neutral point. In this case, the low-voltage winding 4 has a low voltage as well as the upper and lower cylinders.

If a certain percentage of St is attached to the inside of sob, it will play the role of alleviating the electric field at the 4 ends of the low voltage winding, so the upper and lower rings
Even if the thickness of #a, 74) b becomes larger than the thickness of the insulating tube when an insulating tube is used, the insulation distance between the iron core 1 and the insulation tube will not be much larger than when an insulating tube is used. do not have.

As mentioned above, if the upper and lower ends of the inner circumferential side of the inner winding and the outer circumferential side of the outer winding, where the current density is particularly high, of the K1 winding are cooled separately from the cooling duct built into the winding, It is possible to average out the temperature rise within the winding, and the maximum temperature rise of the winding can be lowered without increasing the number of cooling combs within the winding.

In this configuration, the cooling system that is added in particular is the basic insulation tube used to wind the winding conductor, the electrostatic shield that alleviates the electric field at the end of the winding, etc., which is originally necessary to construct the winding. Since it can be easily attached to the structure, according to the present invention, a reasonable cooling effect can be obtained without lowering the space factor of the entire winding.

Effects of the Invention As detailed above, the present invention provides a high-voltage winding and a low-voltage winding in which metal sheets and insulating seeds are layered and wound, a cooling duct having a refrigerant passage appropriately arranged in each of these windings, and The cooling duct is equipped with a conduit for allowing a small amount of refrigerant to accumulate in the cooling duct and an insulating knob connecting the conduit and the cooling duct, and the cooling duct is cooled by circulating the refrigerant in the cooling duct via the conduit. In a transformer that cools the winding by cooling the winding, at least the outer circumferential side of the outer winding and the inner circumferential side of the inner winding are in contact with the open surface of the winding and at a position near the first side edge. In addition, a substantially cylindrical metal body with a conduit formed on the side not in contact with the wrinkled winding is provided, and the conduit of this metal body is
The cooling duct is connected to the conduit through which a refrigerant is accumulated via an insulator/insulator, and the metal body is cooled to cool the winding side surface which generates heat with high current density and is small. Since the maximum temperature rise of the wire is suppressed, the temperature on the winding side, where the current density is high and the temperature easily rises, can be forcibly cooled by this metal cylinder, and the cooling duct built into the winding can Combined with cooling from the inside of the winding, t@maki has the characteristics of efficient cooling, lowering the maximum temperature of the winding, and making it possible to realize high-voltage, high-capacity devices. A pressure stopper can be provided.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a conventional foil-wrapped transformer to structure;
The figure is a graph showing an example of analysis of the magnetic flux distribution within the foil winding, FIG. 3 is an explanatory diagram showing the relationship between the current density at the end of the foil winding and the position in the radial direction of the winding, and FIG. A cross-sectional view of a foil-wound winding showing one embodiment of a foil-wound transformer according to the present invention, FIG.
6 is a cross-sectional view of a foil-wound wire showing another embodiment of the present invention. 1... Iron core, 2... Metal sheet, 3... Insulating sheet, 4... Low voltage winding, 5... High winding 1, 6...
Cooling duct, 1.../y f%8...Condenser a,
9... Water cooler, 10 m, 10 b... Liquid collection pipe, 71 m, 1 l b -... Insulation log, 12... Evening/living, 13... Insulating medium, J 4-・
・Refrigerant tank, 15 ... Refrigerant, 16 m, 1 m
b. 20m, Rob...Ring, 17...Metal cylinder, J
J-"Liquid guide pipe, 19m, 19b... 21-metal cylinder to the opening of the pipe. Applicant's agent Patent attorney Takehiko Suzue 0b Fig. 2 2 φ' o ao (0%t N. Ma (Sho) (Selection Hi/is'g Island Nishikiya)

Claims (1)

[Claims] A foil-shaped high-voltage winding and a low-voltage winding wrapped around the iron core and wrapped with a metal sheet F and an insulating sheet, and each of these windings is appropriately arranged and has a refrigerant passage. It is equipped with cooling ducts, pipes for allowing a small amount of refrigerant to accumulate in these cooling ducts, and an insulating pipe that connects the other pipes and the cooling duct, and for introducing a small amount of refrigerant into the cooling duct via the pipes. When the cooling duct is cooled by cooling the cooling duct, at a static induction amount that provides 1 lkH of cooling from K, at least the outer circumference of the outer winding and the inner circumference of the inner winding g4°, at least the former has a A substantially cylindrical metal body with a conduit formed thereon is disposed in contact with and near the side edge of the winding, and on the side of the surface that does not have the scissor winding KIIL, and the conduit of this metal body is used to supply the refrigerant to the cooling duct. A foil-wound transformer, characterized in that the foil-wound transformer is connected to the conduit for circulation via an insulator.