JPS6028371B2 - transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transformer configured such that the leakage impedance of the tertiary winding is increased.

Generally, in a transformer equipped with a tertiary winding, it is required that the leakage impedance (hereinafter referred to as impedance) of the tertiary winding be increased.

In other words, in a transformer with a tertiary winding that is designed without special consideration, the impedance of the tertiary winding is likely to be 4.0%, and the short circuit current due to a short circuit in the external circuit becomes large, resulting in a large capacity circuit breaker. Is required. Also, the capacity of the tertiary winding is generally smaller than that of the primary and secondary windings, so
It has little resistance to electromagnetic mechanical force acting between the windings due to short-circuit current. Therefore, it is necessary to reduce the short-circuit current flowing through the tertiary winding, which requires increasing the impedance of the tertiary winding. Generally, the impedance of a large capacity transformer is approximately equal to the reactance.

That is, impedance is proportional to the magnetic energy stored in the winding and in the main gap and is expressed by the equation 1}.
%Z=%IX JEurope/dv...{1)
%Z: Percent impedance %IX: Percent reactance B: Magnetic flux density at each part of the winding and main gap v: Volume of each part of the winding and main gap '1} To change the impedance as shown by the formula 'B2・dv There are two ways to do this, one is to mainly change the magnetic density B, and the other is to mainly change the volume v.

For example, in the transformer shown in FIG.
Impedance between the primary winding 1 and the secondary winding 2 (the total volume v of the primary winding 1, the secondary winding 2, and the main gap, 2 and the
The impedance between the secondary winding 2 and the tertiary winding 3 (which is proportional to the magnetic flux density shown in Figure b) is set to a certain value. 23, which is proportional to the magnetic flux density shown in Figure 1), the main gap between the secondary winding 2 and the tertiary winding 3 should be made larger than the required dimension for insulation, as shown in Figure 2 a. However, the disadvantage is that the transformer becomes large and uneconomical. Further, a current limiting reactor may be inserted into the tertiary winding 3, but this has the disadvantage that a separately manufactured current limiting reactor must be attached to the transformer.

The present invention has been made in consideration of the above points, and an object of the present invention is to provide a transformer that can economically increase the impedance of the tertiary winding.

An embodiment of the present invention will be described above with reference to the drawings.

In Figures 3a to 3d, the tertiary winding 3 is attached to the iron core 4 from the inside.
, the supplementary winding 5, the secondary winding 2, and the primary winding 1 are wound in the same circle shape. Then, one terminal b of the tertiary winding 3 and one terminal c of the supplementary winding 5 are connected in a direction that reduces the induced voltage of the tertiary winding 3, and the other terminal a of the tertiary winding 3 and the supplementary winding The other terminal d of the wire 5 is the tertiary terminal a, d, and the tertiary terminal a
, d is configured to be the induced voltage difference between the tertiary winding 3 and the supplementary winding 6. Note that the main gap between the supplementary winding 5 and the secondary winding 2 has a dimension determined from the viewpoint of insulation and cooling. Further, the dimensions of the main gap between the tertiary winding 3 and the supplementary winding 5 are selected so as to provide the required impedance. Next, the effects of the transformer according to the present invention will be explained in comparison with the conventional transformer shown in FIG.

It is assumed that the total volume of the main gap between the primary winding 1 and the secondary winding 2 and the magnetic flux density shown in FIGS. 2b and 3b are the same. That is, the impedance between the primary winding 1 and the secondary winding 2 is made the same. In the transformer shown in Figure 3a, the voltage between the tertiary terminals a and d is V, and the tertiary winding 3 and the supplementary winding 5
If the induced voltages of are respectively E3 and E5, then V=E3-E5. The magnetic flux density at the main gap between the tertiary winding 3 and the supplementary winding 5 is E2/E2 in the case of Figure 2, as shown in Figure 3c.
-E5 times larger. That is, if the impedance between the secondary winding 2 and the tertiary winding 3 in FIGS. 2 and 3 is made the same, the volume of the main gap between the secondary winding 2 and the tertiary winding 3 in FIG. It can be made 4 times smaller than the case in Figure 2.
The same is true between the tertiary winding 3 and the primary winding 1.
Therefore, the outer diameter dimensions of the secondary winding 2 and the primary winding 1 are reduced, the weight of the copper wire is reduced, and the dimensions of the iron core and tank are also reduced, so that the weight of the iron core, the weight of the tank, and the amount of oil are reduced.

On the other hand, the capacity of the tertiary winding 3 is the same as that of the tertiary winding 3, and the supplementary winding 5
However, the tertiary winding capacity is generally small, and the winding is often designed with a margin to withstand short-circuit mechanical force or due to manufacturing requirements, so the percentage increase in the weight of the copper wire is This is often smaller than the weight reduction of the copper wire between the primary winding 1 and the secondary winding 2.

Therefore, a compact and inexpensive transformer with a tertiary winding can be provided. Also, a separately manufactured current limiting reactor is not required. Furthermore, since the supplementary winding 5 is arranged in the same D shape on the same iron as each of the primary winding 1, secondary winding 2, and tertiary winding 3, each of the windings arranged in the same manner Since the wires can be supported in common, the provision of the supplementary winding 5 eliminates the need for a special winding support structure, making it possible to provide a more compact transformer. In the above embodiment, the case where the impedance between the tertiary winding and the primary winding and between the tertiary winding and the primary winding is increased is explained, but when only the impedance between the tertiary winding and the primary winding is increased For this purpose, the supplementary winding 5 may be placed between the secondary winding 2 and the primary winding 1 as shown in FIG. 4a.

With this configuration, as shown in Figure 4c, the magnetic flux density distribution will be much larger than in the case of Figure 3, and therefore the outer diameters of the primary winding 1 and the secondary winding 2 will be much smaller. be able to. Furthermore, a supplementary winding 5 can be arranged outside the primary winding 1, as shown in FIG. 5a.

With this configuration, the magnetic flux density distribution becomes even larger as shown in FIGS. 5b and 5c. As explained above, according to the present invention, the primary winding, the secondary winding, and the tertiary winding are wound around the outer periphery of the wire in the same D shape, and the tertiary winding is arranged at the innermost side. A supplementary winding is connected in series to the tertiary winding so as to reduce the electromotive force of the tertiary winding, and the supplementary winding in parentheses is arranged outside the tertiary winding in the same D shape. As a result, the impedance of the tertiary winding can be made arbitrarily, and the current limiting reactor can be omitted, resulting in a compact, inexpensive, and highly reliable transformer that can reduce overall weight and oil consumption. Can be provided.

[Brief explanation of the drawing]

Figure 1a is a typical transformer winding arrangement where the impedance of the tertiary winding is not particularly large. A schematic diagram showing the magnetic flux density distribution between the wires and between the tertiary winding and the primary winding. Figure 2a is a layout diagram of the transformer winding in which the impedance of the tertiary winding is increased in a conventional transformer. Figure 2b to d are schematic diagrams showing the magnetic flux density distribution between the primary winding and the secondary winding, between the tertiary winding and the secondary winding, and between the tertiary winding and the secondary winding, respectively, and FIG. 3a is according to the present invention. Winding arrangement diagrams showing one embodiment of the transformer, Figures 3b to 3d show the locations between the primary winding and the secondary winding, between the tertiary winding and the secondary winding, and between the tertiary winding and the primary winding, respectively. FIG. 4a is a winding arrangement diagram showing another embodiment of the present invention, and FIGS. 4b to 4d are a schematic diagram showing the magnetic flux density between the primary winding and the secondary winding, and between the tertiary winding and the secondary winding. A schematic diagram showing the magnetic flux density distribution between the secondary windings and the tertiary winding, FIG. 5a is a winding arrangement diagram showing another embodiment of the present invention, and FIGS. FIG. 2 is a schematic diagram showing magnetic flux density distribution between windings, between a tertiary winding and a secondary winding, and between a tertiary winding and a primary winding. 1...Primary winding, 2...Secondary winding, 3...
...Tertiary winding, 4...Iron core, 5...Supplementary winding. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A primary winding, a secondary winding, and a tertiary winding are wound concentrically around the outer periphery of an iron core, and the tertiary winding is arranged on the innermost side, and the tertiary winding is A transformer characterized in that a supplementary winding is connected in series so as to reduce the induced voltage of the tertiary winding, and the supplementary winding is arranged outside the tertiary winding and concentrically therewith. . 2. The transformer according to claim 1, wherein the supplementary winding is arranged between the tertiary winding and the secondary winding. 3. The transformer according to claim 1, wherein the supplementary winding is arranged between the secondary winding and the primary winding. 4. The transformer according to claim 1, wherein the supplementary winding is arranged at the outermost side.