JPS5863110A - Transformer - Google Patents

Abstract

PURPOSE:To prevent the joint surface portion between a cooling duct and a liquid conduit from insulation breakdown, by a method wherein the cooling duct of a transformer is common-connected to liquid introducing members set along the end surface of a winding, and the liquid conduit is connected to the low- voltage winding side portion of the liquid introducing members. CONSTITUTION:The refrigerant carriers transmitted by a pump 7 enter a lower liquid introducing member 101 through a lower conduit 10 and joint pipe 103. The refrigerant carriers, then, are branched into each of the cooling ducts 6,6, cool the winding, and vaporized. The vaporized refrigerant carriers join again in the conduit 101, flowing into a condenser 8 through an upper joint pipe 103 and conduit 10. In this transformer, the cooling ducts 6,6 are not connected to the conduit 10 directly through the insulating pipe, so no insulation breakdown occurs on the cooling duct joint portion. In addition, the voltage load on the a conduit joint portion is lowered because the joint position of the conduit 10 for the liquid introducing members 101 is on the low-voltage side. Thereby no surface insulation breakdown occurs on this portion, too.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transformer comprising a foil winding formed by overlapping metal sheets and insulating sheets, and having a built-in cooling duct through which a refrigerant is passed.

Foil-wound transformers with foil-wound windings have a good space factor and are small and compact.
Because it has the feature of being lightweight (=, a few kV, a small capacity transformer with a relatively low voltage of about several 100 kV4)
Most of them have already been put into practical use and are widely available on the market.

Recently, research has been conducted on expanding the transformer to higher voltage/larger capacity transformers, such as 275kV and 300MvA transformers, but the biggest key is how to improve cooling capacity and high insulation capacity. This depends on whether the windings can be equipped with the following: Although such high-voltage, large-capacity transformers have not yet been put to practical use, the cooling method for this foil-wound transformer is that A so-called heat pipe type system is being considered in which the heat generated from the winding loss is directly cooled by storing (c) a refrigerant with excellent insulating properties.

Figure 1 shows what is conventionally considered as a foil-wound transformer with such a cooling method.
(2-wound low-voltage winding; 5 is a high-voltage winding wound outside the low-voltage winding 4 via an insulating barrier 9;
These windings 4.5 are foil-wound windings in which the metal sheet 2 and the insulating sheet 3 are layered and wound. Reference numeral 6 denotes a cooling duct made of an insulating material built into the winding 4°5 yen (-), and this cooling duct 6 is a thin flat duct curved into a substantially cylindrical shape, A refrigerant such as Freon-113 or F'075 is passed through the cooling duct 6, and as it passes through the cooling duct 6, the refrigerant winds the windings. The windings are cooled by using the latent heat of vaporization of the refrigerant to cool the windings.Then, this refrigerant is cooled and condensed by water cooling in the condenser 8.
The liquefied refrigerant is stored in the refrigerant tank 14 (= stored in the pump 7
(The refrigerant circulation circuit and the transformer are separated from each other.Also, the liquid guiding pipe 10 that receives the refrigerant is made of metal such as stainless steel.
An insulated pipe 11 is used to connect it to the cooling duct, and the liquid guide pipe 1o is insulated from the ground potential of the tank 12 and the like. The potential of the cooling duct is electrically (=coupled) to the same potential as the winding (because it is wound twice).In addition, the insulation of the winding is the tank circle (=filled with insulating oil or It is insulated with an insulating medium such as SF or gas.

1111 Note that in FIG. 1 (-), winding lead wires that are not directly related to the present invention, bushings that lead them out to the outside of the tank, etc. are omitted.

The transformer of this cooling method is completely separated from the circulation circuit through which the refrigerant flows for cooling and the insulating medium 13 for insulation.For this reason, the foil-wound transformer of this method is Here, it is referred to as a separate foil-wound transformer.

Transformers using this cooling method utilize the latent heat of vaporization of the refrigerant, so you can expect excellent cooling characteristics.

Large capacity transformer (= promising.

However, in the conventional transformer described above, although the pipe 11 that connects the cooling duct 6 built into the winding and the liquid guide pipe 10 is insulated, Pipe 11 (- because the applied voltage increases (-
1 Leakage occurs along the surface of the insulated pipe. There was a problem of insulation breakdown in the transformer.

The present invention has been made in view of the above-mentioned points, and its purpose is to provide a highly reliable, high pressure (2) To provide a transformer that can realize

That is, the transformer of the present invention, like a conventional transformer, has two separate cooling ducts (= direct liquid conduction pipes (= directly connected through insulated pipes).
=Instead of connecting each cooling duct to the winding end face (=liquid guiding member placed along the winding end face (=liquid guiding member placed along the winding end face) (=commonly connected, and connecting the liquid guiding pipe to the low voltage winding side portion of this liquid guiding member) Since this transformer is connected to an insulating liquid guide member (not directly connected to the cooling duct), there is no problem of creeping dielectric breakdown at the connection part of the cooling duct. However, since the connection position of the liquid guide pipe to the liquid guide member is on the low pressure side (two liquid guide pipes W connection part (1), since the applied voltage is quite low, there is no creeping dielectric breakdown in this part, and therefore its reliability is low. Since it is quite high, high pressure can be achieved.

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

In Figure 2, 101 in Figure 1 is the low voltage winding 4 and the high voltage winding 5.
It is a liquid guiding member made of an insulating material such as Teflon (tetrafluoroethylene), which is provided along both the upper and lower end surfaces (-) of a winding consisting of a winding, and this liquid guiding member 101 is illustrated in FIG.
- As shown in (2), it is a flat disc-shaped hollow container with a central part (= core main leg insertion hole). A part of the solid wall of the hole (two liquid guide pipe connection ports are provided, and a gold maple fattening liquid pipe 10 for guiding the refrigerant is connected to this liquid guide pipe connection port via an insulating connecting pipe 103). In addition, both ends of the low-voltage winding 4 and the high-voltage winding 5 (two built-in cooling ducts 6.6
are commonly connected to each other.

Note that the same parts as those shown in Figure 1 (-) in Figure 2 (=) are given the same reference numerals in the figures and their explanations are omitted. 6 is the same as the conventional one, and the tank 12 yen is also filled with an insulating medium such as insulating oil or 8F gas.

Therefore, the refrigerant sent by the transformer (2) and the pump 7 (-) are transferred to the lower liquid guide pipe 10 and the connecting pipe 1.
03, enters the lower liquid guiding member 101 yen, is divided into each cooling duct) 6.6, cools the winding in the process of passing through each cooling duct 6.6 yen, and further (2 evaporated refrigerant is They join together at the upper liquid guide member 101 (2), pass through the upper connecting pipe 103 and the liquid guide pipe 10, and enter the condenser 8 (==).

And this transformer is similar to the conventional transformer (1 each cooling duct 6. 6 insulated pipes (2) direct liquid conduit 10 (=
Since it is not connected, there is no problem of creeping dielectric breakdown at the cooling duct connection part that occurred in conventional transformers.
Since the connection position of 0 is on the low pressure side (1 liquid guide pipe connection (=
Although the applied voltage is quite low, there is no dielectric breakdown at this part. In addition, this transformer (second part).

There is also an advantage that the liquid guide member 101 serves as an insulator that blocks the space between the windings 4 and 5 and the liquid guide pipe 10.

Note that in the above embodiment, a disc-shaped hollow container is used as the liquid guiding member 101, but as this liquid guiding member 101,
For example, you can use a spiral insulating pipe as shown in Figure 4 (-), or a circular insulating pipe as shown in Figure $5 (two-part link-shaped pipe connected via a communicating pipe). Good too.

As described above, in the transformer of the present invention, insulating liquid guide members are arranged along both end faces of the winding, and both ends of each cooling duct built in the winding are connected to the liquid guide member. (-1) A liquid guiding pipe for guiding the refrigerant to be passed through the cooling duct is connected to the low voltage winding side portion of the liquid guiding member (=
Since it is characterized by a connection, there is no problem of creeping dielectric breakdown at the connection between the cooling duct and the liquid guide pipe, and therefore, reliability is high and high pressure can be realized.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a conventional transformer, Sections 2 and 3 are sectional views showing an embodiment of the present invention and a perspective view of a liquid guiding member, and Figs. 4 and 5 are respectively It is a perspective view which shows the modification of a member. 1... Iron core main landing gear, 2... Metal sheet, 3... Absolute 1
1# sheet, 4...low voltage winding, 5...high voltage winding, 6
...Cooling duct, 10...Liquid guide pipe, 1o1...Liquid guide member, 102...Liquid guide pipe connection port, 103...Connecting pipe. Applicant's agent Takehiko E Takehiko Patent attorney 0 Figure 1 8 11 10 Figure 2

Claims (3)

[Claims] (1) It is equipped with a low-voltage winding and a high-voltage winding made of foil-wound windings made by overlapping metal sheets and insulating sheets, and inside these windings (= multiple cooling ducts through which refrigerant passes) In the device, insulating liquid guide members are arranged along both end faces (== of the windings), and both ends of each of the cooling ducts are connected in common to the liquid guide members (==, and the cooling ducts (== are connected together). A transformer characterized in that a liquid guide pipe for guiding a refrigerant to be passed through is connected to a low voltage winding side portion (-) of the liquid guide member. (2) The transformer according to claim (1), wherein the conductive member comprises a disc-shaped hollow container. (3) The transformer according to claim (1), wherein the conductive member is a spiral pipe. (41) The transformer according to claim 11, characterized in that the conductive members are connected via a plurality of ring-shaped communicating pipes arranged inside and outside. Claim 11 is characterized in that the is connected to the conductive member via an insulating connecting pipe.
) to @+41 (the transformer described in 2).