JPH01107507A - Three-phase transformer with tertiary winding - Google Patents

Abstract

PURPOSE:To perform a compact three-phase transformer with a tertiary winding which has less eddy current losses of a tank and lead vicinity structure by specifying the rise of winding leads. CONSTITUTION:A delta-connected tertiary cylindrical first winding layer 2, a second winding layer 2, parallel winding cylindrical tap winding first winding layer 4, a second winding layer 5, a star-connected low voltage winding 6 and a high voltage winding 7 are concentrically wound from inside on a core 1, the leads 8, 9 of the windings 2, 3 are both extended upward, the windings 4, 5 are connected in series at its upper end, and its leads 10, 11 are extended downward. Thus, the number of leads rising from between phases can be reduced, and eddy current losses generated in a tank and a lead vicinity structure can be decreased.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a three-phase transformer with a tertiary winding.

(Prior Art) Generally, a single-layer cylindrical winding in which parallel conductors are wound in parallel in the axial direction is used for the tertiary winding of a three-phase transformer. In this case, since the ends of the windings are located above and below the windings, it is necessary to raise the lower part of the windings to the upper part at the phase part of the windings. In addition, tap winding often uses side-by-side cylindrical winding, in which multiple conductors constituting each tap are wound side by side in the axial direction. In order to connect the windings in series, it is necessary to raise the leads upward between the winding phases. The number of start-up leads is (N-1), where N is the number of strands constituting each tap, and generally increases as the number of taps increases.

Normally, in the case of a transformer with a tertiary winding, the number of windings is large, so it becomes difficult to set up the leads in the interphase portion due to the space and the structure is complicated. In order to deal with this, the size between the winding and the tank can be increased, but this increases the weight and amount of oil and also increases the transportation size.

In the case of a large-capacity power transformer, the voltage of the tertiary winding is generally as low as about 11 to 30 KV, so the current is about several KA. In addition, the current flowing through the side-by-side cylindrical tap windings is about 1 to 2 KA at most, but for the upper and lower leads, the currents of each lead are superimposed and leakage magnetic flux is generated, so the current is about 1 to 10 KA. This may be equivalent to having a lead through which a current of

At a portion where such a large current lead is drawn out or raised along the tank, leakage magnetic flux causes eddy current loss in the tank or other nearby structures.

In order to solve these problems, conventionally, a two-layer cylindrical winding as shown in FIG. 2 has been used as a tertiary cylindrical winding or a side-by-side cylindrical tap winding. This winding is made by arranging a plurality of conductors in the axial direction and winding them from the top to the bottom to form the second winding layer 21, and at the bottom end of the winding, two windings are made in order from the conductor that is wound first! 22, the second winding layer 22 is wound on top of the second winding layer 21 from the bottom to the top via a spacer 23 for ensuring the amount of oil and insulation. Because of this structure, the winding leads 24 and 25 are both pulled out from the upper side, so there is no need to raise the winding leads from the interphase part, and eddy current loss on the tank wall and structures near the leads can be reduced. can be reduced.

Figure 2 shows a case where the number of conductors wound in parallel in the axial direction is four. If these are used as parallel conductors, it will be the same as a normal cylindrical winding, and each conductor will be connected in series at the top. By connecting them so that

(Problems to be Solved by the Invention) Fig. 3 shows a tertiary cylindrical winding, a side-by-side cylindrical tap winding, and a secondary cylindrical tap winding.
The figure shows a conventional example when the two-layer winding structure is adopted, and shows a tertiary winding first winding layer 2, a second winding layer 3, and a tap winding first winding, which are triangularly connected to the iron core 1 from the inside. layer 4, second winding layer 5,
The low voltage winding 61 is connected in a star shape.The high voltage winding 7 is connected in a star shape, with the line end outlet drawn out from the center of the winding (vertical distribution structure). Leading out 8°9, leading out of tap windings 4 and 5 10.11. Low voltage winding 6
connection end outlet 12 and high voltage winding neutral point outlet 1
3 is pulled out from the top, the line end outlet 14 of the high voltage winding 7 is pulled out from the center of the winding, the neutral point side outlet 15 of the low voltage winding 6 and the neutral point side outlet 1 of the high voltage winding 7.
The other end of 3 is pulled out from the bottom. An example of the general bushing arrangement of the transformer in this case is shown in Fig. 6.
A high pressure bushing 16 is attached to one long side of the main body tank 15.
Low pressure bushing 17 on the other side, tertiary bushing 18 on one end of the short side. A three-phase on-load tap changer 19 is arranged at the other end.

In this case, it is necessary to pass between the iron core at the top of the first winding and the tank for all three phases, the tertiary winding leads 8 and 9 to the tertiary bushing 18 side, and the tap winding leads 10 and 11 to the tap changer 19 side. The upper part of the high-voltage bushing 16 on the long side of the 6-body tank 15 has a relatively large space through which the neutral point lead of the high-voltage winding with a low connection class passes, and the connecting lead of the tertiary winding or the tap winding. There is room to pass either of the wire connection leads, but on the low pressure bushing 17 side,
Line end exit 12 of low voltage winding which originally has relatively high voltage
There is a problem in that it becomes very difficult to pass around the remaining one of the tertiary winding connection lead or the tap winding connection lead because it passes to connect to the low voltage bushing 17.

The purpose of the present invention is to reduce eddy current loss in the tank and structures near the outlet by reducing the rise of the winding leads, and to make it compact and easy to move around the leads in the tank, reducing the size of transportation. An object of the present invention is to provide a three-phase transformer with a tertiary winding.

[Structure of the invention]

(Means for Solving the Problems) A three-phase transformer according to the present invention has two winding layers formed by winding a plurality of parallel conductors arranged in the axial direction around a three-phase core placed in a tank. A tertiary cylindrical winding connected in series and two winding layers formed by axially winding multiple conductors forming each tap are connected in series to form a side-by-side cylindrical tap winding and low voltage winding. .

In the case where high voltage windings are arranged concentrically for each phase,
The tertiary cylindrical winding of each phase has a winding start and a winding end of the first and second winding layers at the upper ends, respectively.

The leads of the first winding set and the second winding layer are connected to each other in series at the lower ends, and the lead leads of the first winding set and the second winding layer are respectively pulled out upward, and the side-by-side cylindrical tap windings of each phase are connected to the first and second winding layers. The winding layer has the winding start and winding end at the lower end,
The windings are connected in series to each other at the upper ends, and the lead leads of the first winding layer and the second winding layer are each pulled out downward.

(Function) With this configuration, the number of leads raised from the interphase portion can be reduced, and eddy current loss generated in the tank and structures near the outlet can also be reduced.

Furthermore, it is possible to easily move the lead wires around inside the tank, and it is possible to supply a compact three-phase transformer with a tertiary winding that is small in transportation size.

(Example) A three-phase transformer with a tertiary winding according to the present invention will be described below with reference to FIG.

In FIG. 1, tertiary cylindrical windings are triangularly connected from the inside to the iron core 1, a first winding layer 2, a second winding layer 3, a side-by-side cylindrical tap winding, a first winding layer 4, and a second winding layer. Layer 5, star-connected low-voltage winding 6, star-connected high-voltage winding with vertical distribution structure
7 are wound concentrically.

The above-mentioned tertiary cylindrical windings 2 and 3 have both the beginning and the end of the winding at the top, and are connected to each other in series at the lower ends, and the lead wires 8 and 9 are both drawn upward, and the above-mentioned side-by-side winding cylindrical tap winding 4 and 5 have the winding start and winding end both at the bottom, and are connected in series to each other at the upper end, and the lead wire 10.11
are both pulled downward.

Tertiary cylindrical windings 2, 3 and side-by-side cylindrical tap windings 4, 5
By adopting a two-layer cylindrical winding, the number of rising leads in the interphase area can be reduced.
In addition, as previously explained, it is possible to reduce eddy current loss due to leakage magnetic flux due to lead leads in the tank and structures near the lead. Explain that leash crawling can be made easier.

In this case as well, the arrangement of each bushing of the transformer is as follows, taking Figure 4 as an example:
When extending the openings 8 and 9 of the tertiary cylindrical windings 2 and 3 to the tertiary bushing 18 side for all three phases, and the openings 10 and 11 of the side-by-side wound cylindrical tap windings 4 and 5 to the tap changer 19 side, The upper part of the high pressure bushing 16 side on the long side is
Only the neutral point lead of the high-voltage winding with a low insulation class passes through it, and the tertiary winding connection lead, which is exposed from the upper part of the winding, can be easily passed through. In addition, by arranging the two leads of each phase connected from the output leads 8 and 9 of the tertiary winding to the bushing as parallel as possible,
Since leakage magnetic flux caused by each lead current can be canceled out, eddy current loss generated in surrounding structures and tanks can be reduced.

On the other hand, the tap winding lead 10.11 is brought out from the bottom of the tap winding 84.5, so after making the crossover connection between the taps near the lead, the iron core at the bottom of the winding near the tank length is At the bottom of the 0 winding, which needs to be connected to the three-phase load tap changer 19 through the tank and tank, the neutral point lead of the high voltage winding is on the high voltage bushing 16 side, and the low voltage winding's lead is on the low voltage bushing 17 side. Since there is only a lead with a low insulation class along with the neutral point lead, it is easy to connect to the on-load tap changer 19 through the tap winding connection lead using either side or both sides. Also tap winding 4.
5 to the on-load tap changer 19 for each phase,
(N+1) leads are connected, but the crossover connections between taps are made near the openings.

Current only flows through one of these lines, and eddy current loss in this part does not pose a problem.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to reduce the rise in the phase-to-phase portion of one winding lead.

As a result, it is possible to provide a compact three-phase transformer with a tertiary winding, which has less eddy current loss in the tank and the structures near the outlet, makes it easy to move the leads around, and is small in transportation size.

[Brief explanation of the drawing]

Fig. 1 is a wiring diagram showing an embodiment of the present invention, Fig. 2 is a structural diagram of a two-layer winding structure, Fig. 3 is a wiring diagram showing an example of a conventional three-phase transformer, and Fig. 4 is a wiring diagram showing an example of a conventional three-phase transformer. It is a top view which shows an example of arrangement|positioning of the bushing of a phase transformer, and an on-load tap changer. DESCRIPTION OF SYMBOLS 1... Iron core, 2... The tertiary cylindrical winding first winding layer, 3... The same second winding layer. 4... Second winding layer of side-by-side winding cylindrical tap winding, 5... Second winding layer, 6... Low voltage winding, 7... High voltage winding,
8, 9...Tertiary winding lead, 10.11...
Tap winding lead out, 12...Low voltage winding line end lead out. 13... High voltage winding neutral point end exit, 14... High voltage winding line end exit. 15...Low voltage winding neutral point end exit. 16...High pressure bushing, 17...Low pressure bushing, 18...Tertiary bushing, 19...Three-phase on-load tap changer. 21... The second layer of the two-layer structure cylindrical winding, 22... The second layer of the two-layer structure cylindrical winding. 23... Spacer, 24.25... Opening. Agent Patent Attorney Yudo Ken Chika Ken Daishimaru Fig. 1 Fig. 3 Fig. 2 Diagram/b Fig. 4

Claims (1)

[Claims] 1) A tertiary cylindrical winding made by connecting two winding layers in series around a three-phase iron core placed in a tank, and two cylindrical windings made by winding multiple conductors configuring each tap in parallel in the axial direction. In a three-phase transformer with a tertiary winding in which a side-by-side cylindrical tap winding formed by connecting winding layers in series, a low voltage winding, and a high voltage winding are arranged concentrically for each phase, the tertiary cylindrical winding of each phase is The winding start and winding ends of the first and second winding layers are held at the upper end, and are connected in series to each other at the lower end, and the lead leads of the first winding layer and the second winding layer are respectively pulled out upward. , the side-by-side wound cylindrical tap windings of each phase have the winding start and winding end of the first and second winding layers at the lower end, respectively, and are connected in series to each other at the upper end, and the first winding layer and the winding end are connected to each other in series at the upper end. A three-phase transformer with a tertiary winding characterized in that the output leads of the two winding layers are each pulled out downward.