JPS5893206A - Transformer - Google Patents

Abstract

PURPOSE:To eliminate the concentration of electric field at the upper and lower end parts of windings as well as increase in an axial mechanical force when short-circuited by a method wherein foil wound coil is supported from below to prevent slippage between winding layers due to vibrations during transportation. CONSTITUTION:A cooling dust 6 is so arranged that its lower end will not project from the low end of winding, and both introducing pipings 9a, 9b on inlet and outlet sides are disposed above windings 4, 5. Both refrigerant inlet and outlet of the cooling duct 6 are also provided on the upper end side of the duct. With this, introducing pipings and introducing pipes are eliminated from the lower side of the windings 4, 5. Instead, insulating plates 20, 21 and 22 are at tached to the lower surface of the windings 4, 5 and then supported by a core fastening fixture 23. By so doing, the windings can be supported from below, thereby to prevent slippage between the winding layers due to vibrations during transportation. It becomes also possible to eliminate concentration of electric field at the possible to eliminate connection of electric field at the upper and lower end parts of the windings as well as increase in an axial mechanical force when short-circuited.

Description

[Detailed description of the invention] The present invention relates to a transformer using foil-wound windings.

Technical background of the invention A transformer using a foil-wound wire made by overlapping metal sheets and insulating sheets has the advantage that the winding has a good space factor and can be made into a small rod. The vessel is number 1 (V
, small-capacity transformers with relatively low pressure of several lOOkvA have already been put into practical use and are widely available on the market.

Recently, in view of its excellent advantages, higher voltage and larger capacity (D
Research is being done to expand its application to F voltage transformers, such as 275kV, 300MVA transformers, but the key lies in how to improve the cooling capacity and provide high P edge force to the windings. Although such a large-capacity KN voltage transformer has not yet been put into practical use, the cooling method for this foil-wound transformer is to incorporate a cooling duct inside the windings to feed a refrigerant with excellent insulation properties. A so-called heat pipe type is being considered, which cools the heat generated from winding loss in an M-tangential manner.

Figure 1 shows what is conventionally considered as a foil-wound transformer with such a cooling method.
A low-voltage winding 5 is wound on the outside of an insulating cylinder 7 which is combined with the low-voltage winding 4, and a high-voltage winding 5 is wound on the outside of an insulating barrier 8 formed on the outside of the low-voltage winding 4. The wires 4 and 5 are foil-wound wires in which a metal sheet 2 and an insulating sheet 3 are layered and wound. Lead wires 16 are connected to both ends of the metal sheet of the winding 4.5, and a line end bushing 17 is drawn out from the upper end of the winding and attached to the top surface of the tank 15.
It is connected to the. Reference numeral 6 denotes cooling ducts made of metal such as stainless steel, which are built in at appropriate locations within the foil-wound windings 4.5. L is approximately cylindrical and curved, and is wound together in the winding. A refrigerant such as Freon R-113 or Fe12 is passed through the cooling duct 6.

1 to 3, 9a is an inlet Ill liquid guide pipe for guiding the refrigerant circulating through the cooling duct 6, 9b is an outlet side liquid guide pipe, and the inlet side liquid guide pipe 9a is a winding 4.5 and is connected to the refrigerant inlet 11aK of the cooling duct 6 via the first liquid guide pipe 10a. Further, the outlet 4All liquid guide pipe 9b is installed below the windings 4 and 5, and is connected to the refrigerant outlet 11b of the cooling duct 6 via the liquid guide pipe 10b. Liquid guide pipe 9m, 9b
are made of metal such as stainless steel, but the liquid guide pipes 4a and 10b are insulating pipes made of Teflon (tetrafluoroethylene resin), etc., and the cooling duct 6 and the liquid guide pipes 9a*9b The twisted liquid guide pipes 9m and 9b are electrically connected to the earth potential of the tank 14, and the cooling duct 6 is installed in the windings 4 and 5, and is in close proximity to the windings 4 and 5. It is electrically connected to the same potential as the winding.

The refrigerant supplied to the cooling duct 6 cools the windings by absorbing the heat generated in the windings with the latent heat of evaporation of the refrigerant while passing through the duct, and the refrigerant leaving the cooling duct 6 enters the condenser 12. The refrigerant is cooled and condensed by water cooling, and the liquefied refrigerant enters the refrigerant tank 13 and is passed through the cooling duct 6 by the pump 14.
sent to.

Further, an insulating medium such as insulating oil or SF6 gas is sealed in the tank 15, and insulation of each part of the winding 4.5 is ensured by this insulating medium.

In transformers using this cooling method, the circulation circuit through which the refrigerant for cooling flows and the insulating medium for insulation are completely separated (separated from each other). For this reason, this type of foil-wound transformer is particularly called a separate foil-wound transformer.

This cooling type transformer utilizes the latent heat of vaporization of the refrigerant, so it can be expected to have excellent cooling characteristics, making it a promising candidate for high-voltage, large-capacity transformers.

5- Problems with the Background Art However, the conventional transformer described above has a liquid guiding pipe 9al which constitutes a refrigerant circulation path above and below the winding. 9b and liquid guide tubes 10a and 10b that connect the liquid guide pipe and the cooling duct 6.
Due to the fact that it is not possible to provide a support member to support the winding 4゜5, each winding layer of the winding may shift vertically (winding @ 1 direction) due to vibration during transportation. There is a risk that the metal sheets facing each other with an insulating sheet in between may shift vertically.Especially in high-capacity L transformers, the outer diameter of the winding is large and the weight is therefore heavy. Since the gap between the windings becomes large, there is a problem in that not only the electric field is concentrated at the upper and lower ends of the winding, but also the axial mechanical force at the time of contact becomes excessive.

Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances, and its object is to support the foil-wound winding a from below to prevent gaps between the winding layers of the winding wire due to vibrations during transportation. 6- A highly reliable transformer that can eliminate the problems of electric field concentration at the upper and lower ends of the windings and increase in axial mechanical force during cross-circuiting caused by misalignment between metal sheets. Our goal is to provide the following.

Summary of the invention That is, the transformer of the present invention is provided with a cooling duct in such a manner that its lower end does not protrude from the lower end of the winding, and an inlet-side liquid guide pipe and an outlet-side liquid guide pipe both arranged above the winding. Further, a refrigerant inlet and a refrigerant outlet of the cooling duct are both provided on the upper end side of the duct, and connected to each liquid guide pipe above all windings of each liquid guide pipe connected to the refrigerant inlet and refrigerant outlet, respectively, An insulating plate is provided on the lower end surface of the winding, and this insulating plate is supported by the iron core clamping fitting. With this configuration, the winding can be supported from below. , it is possible to prevent displacement between the layers of the winding due to vibration during transportation.

Examples of the invention Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

4 In Figures 1 and 5, 4 and 5 are foil-wound windings on the low-voltage side 1 and the direct voltage side, which are made by overlapping and wrapping a metal sheet 2 and an insulating sheet 3 that is slightly wider than the metal sheet 2. All 16 lead wires of windings 4 and 5 are drawn out from the winding end. This is a cooling duct that is wound inside a six-piece winding 4.5, and this cooling duct 6 has a configuration as shown in the diagram of the body 6. That is, this cooling duct 6 is a thin duct that is curved into a cylindrical shape with one side cut off.
A large-diameter liquid guiding path 6a is formed along the circumferential direction at the upper end, and the lower end has the same thickness as the central part of the duct, and the opposite duct side at the separation part. A riser 18 is provided in the HA between edges a+b. The lower end of this riser v18 is connected to one of the duct side edges a, l) at its lower end, and the upper end of this riser pipe 18 is led out slightly above the upper end of the duct and serves as the refrigerant inlet 11a. ing. Ota,
The refrigerant outlet 11b of the cooling duct 6 is provided on the liquid guide path 6a at the upper end of the duct, and the refrigerant outlet 11b is located near the duct side ridge on the opposite side from the duct side edge a to which the riser pipe 18 is connected. It is located in As shown in FIGS. 4 and 5, the six cooling ducts are arranged so that their lower ends are positioned above the lower ends of the insulating sheets 3, and the lower ends of one duct are positioned above the lower ends of the windings 4 and 5. It is set so that it does not protrude.

On the other hand, the refrigerant circulating through the cooling duct 6 is guided, and the inlet side liquid guide pipe 9a and the outlet 1I11 liquid guide pipe 9b are both piped above the windings 4 and 5.
Each liquid guide/mother ide 10a, 10b connected to the refrigerant population 11h and the refrigerant outlet 11b, respectively, is connected to each liquid guide pipe 9a, 9b above the windings 4, 5.

In addition, the lower end of the winding 4.5 is connected to the gap between the insulating sheets 3 (the gap below the metal sheet 2 and the cooling duct 6)'f: the insulating material 19, as shown in FIG. It has a closed configuration. This insulation material 19 is provided by wrapping insulating tape together with the winding 4.5 when manufacturing it, or by filling it with a filler such as insulating varnish after the winding is manufactured. As a result, the lower end surfaces of the windings 4 and 5 are planar. 14 and 5, 20.21 is a ring-shaped insulating plate provided in surface contact with the lower end surface of each winding 4, 5, and supports 22Fi insulation 20.21 from the bottom ill. It is a wide ring-shaped insulating plate, and is supported from below by a core clamping fitting 23 having 22 insulating plates.

In addition, in Figure 4, the same symbols as those shown in Figure 1 are used in the drawing, and the name of the ship is omitted.

That is, in this transformer, the cooling duct 6 is provided so that its lower end does not protrude beyond the lower end of the winding, and both the inlet side liquid guide pipe 9a and the outlet side liquid guide pipe 9b are connected to the windings 4 and 5.
The refrigerant inlet 11a of the cooling/vent 6
and the refrigerant outlet 11b are both provided on the upper end side of the duct,
-10- The liquid guide pipes 9a are connected to each of the liquid guide pipes 10m and 10b connected to the refrigerant inlet 11a and the refrigerant outlet 11b, respectively, in a square of the winding 4.5.

By connecting 9bvC, there is no liquid guide pipe or liquid guide pipe on the lower side of the windings 4 and 5, and insulating plates zo and 2z'6 are provided on the lower end surfaces of the windings 4 and 5. These insulating plates 20 and 21 are supported by the core clamping fitting 23 via another insulating plate 22. With this configuration, the windings 4 and 5 can be supported from below. Therefore, it is possible to prevent displacement between the winding layers of the windings 4 and 5 due to vibration during transportation.

In the above embodiment, an insulating plate is provided in two layers below the winding 4.5, but this insulating plate may be provided in only one layer, or the insulating plate provided between the insulating sheets at the lower end of the winding The material 19 is not necessarily required.

1. In the above embodiment, the cooling duct 6 is configured as shown in FIG.
Any configuration may be used as long as the refrigerant outlet 1a and the refrigerant outlet 11b are provided on the upper end side. 7EQ+-FIG. 10 shows an embodiment of the cooling duct 6, in which the cooling duct shown in FIG. 1 duct side edge a,
b are respectively lined with W gauze, and the refrigerant outlet 11b is provided at the opposite side 1 of the separation part. FIG. 8 shows the cooling duct 6f shown in FIG. 7 of a split type. In addition, the furnace 6
The cooling duct 6 shown in FIGS. 8 to 8 may be used with the refrigerant inlet 11a and cold tofu outlet 11b reversed. Sunta, 9th
The six cooling ducts shown in FIG. - Vertical partition plates 24 and 24 are installed to allow the refrigerant flowing in from the upper end of the duct to flow as shown by the broken line arrow in the figure, and then to flow out again from the upper end of the duct. An example is shown in the case of a 1-duct, and FIG. 10 shows an example in the case of a split duct.

Effects of the Invention Since the transformer of the present invention has the above configuration,
By supporting the foil-wound winding from below, it is possible to prevent displacement between the layers of the winding due to vibrations during transportation. Therefore, it is possible to prevent the concentration of 1' field at the upper and lower ends of the winding and the smoke path caused by the displacement between the metal sheets. It is possible to improve reliability by eliminating the problem of an increase in axial mechanical force at the time of operation.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional transformer, FIGS. 2 and 3 are perspective views of a cooling duct used in a conventional transformer, and an enlarged sectional view of a portion thereof. FIG. 5 is an enlarged view of the lower end portion of the winding shown in FIG. 4; FIG. 6 is a perspective view showing an example of the cooling duct used in the transformer of the present invention; FIG. 1 to 10 are perspective views showing modified examples of cooling ducts used in the transformer of the present invention. 4.5...Foil-wound winding, 6...Cooling duct, 9a...
・Supply side liquid guide pipe, 9b...Return side gutter liquid pipe, lOa
. -13= 10b...Liquid guide pipe, 11a...Refrigerant inlet, ll
b... Refrigerant outlet, 20.21.22... Insulating plate, 2
3... Iron core tightening fittings. Applicant's agent Patent attorney Takehiko Suzue-14= ○ O N N \j 53-

Claims (1)

[Claims] An iron core, a foil-wound winding provided on the outside of the main legs of this iron core, a cooling duct built into this winding, and a refrigerant circulating through this cooling duct. and an outlet side liquid guide pipe, a liquid guide pipe connecting the inlet side liquid guide pipe and the refrigerant inlet of the cooling duct, and a guide connecting the outlet side liquid guide pipe and the refrigerant outlet of the cooling duct. In a transformer equipped with a liquid main tube, the cooling duct is provided so that its lower end does not protrude from the lower end of the winding, and both the inlet side liquid guide pipe and the outlet side liquid guide pipe are arranged above the winding. Further, the refrigerant inlet and refrigerant outlet of the cooling duct are both provided on the upper end side of the cooling duct, and each liquid guide pipe connected to the refrigerant inlet and refrigerant outlet, respectively, is connected to the above-mentioned liquid guide pipe above the winding. , and the lower end surface of the winding is supported by an iron core clamping fitting via an insulating plate.