JPS5929129B2 - transformer winding - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in transformer windings.

Generally, the single-phase wiring diagram of an autotransformer that maintains the medium voltage constant and switches only the high voltage is configured as shown in Figure 1, with one end of the series winding 21 connected to the high voltage line terminal U. The other end of the shunt winding 23 is connected to the intermediate voltage line terminal u and one end of the shunt winding 23 via the tap winding 22, and the other end of the shunt winding 23 is connected to the neutral point terminal.

The openings 24 provided in the tap winding 22 are tertiary windings 12 to 18, and a and b are tertiary J-order terminals.

In the case of this system, assuming that the voltage switching range is ±10%, the switching capacity of the tap winding 22 is approximately 20% of that of the series winding 21 because it is an autotransformer.

As a result, when the tap winding 22 is placed adjacent to the series winding 21, when the transmission voltage is an ultra-high voltage of 500 kV or 400 kV, the corresponding shock test voltages are set to 1550 kV and 1425 kV, respectively, as is well known. 3 of the shock test voltage entering from the high voltage line terminal U.
Since 0% to 40% is transferred to the tap winding 22, it is necessary to strengthen the insulation of the tap winding 22 and the tap changer to withstand this transition voltage. Therefore, in order to improve this drawback, generally, as shown in FIG. is suppressed. On the other hand, as the voltage of medium-voltage line terminal u has become 275 kV and 220 kV due to the ultra-high voltage of power transmission in recent years, the corresponding shock test voltage is 1050 kV and 1900 kV, so it is necessary to suppress the transition voltage. The structure shown in FIG. 2 alone is no longer sufficient, and it is becoming necessary to also strengthen the insulation as described above.

Further, as shown in FIG. 3, openings 12, 13, 14, 15, 16, 17 are pulled out from the upper part of the tap winding 22, and openings 13A, 14A, 15A, 16 are pulled out from the lower part.
Since 7A, 17A, and 18 are drawn out, there is a drawback that a huge amount of manufacturing work is required for forming/forming and insulating the P lead wires. As shown in Figures 4 and 5,
The tertiary winding 24, the double tap winding 22, the shunt winding 23, and the series winding 21 are wound concentrically from the inner diameter side of the iron core i in this order. It has a structure in which the outer layer is turned around, folded back at the lower end, and further wound around the outer diameter side layer to the upper part. This will be explained in detail with reference to FIG. 6.

FIG. 6 shows a case where the tap winding 22 is made up of 26 conductors, and the winding start lead 220 enters from the top, and the tap winding 22 has 6 conductors in the axial direction.
The lined inner layer 221 is wound spirally to the lower end, and then the six layers are rolled up to the outer diameter side at the lower end, and then the outer layer 222 is rolled up to the upper end in the same way as the inner layer 221. The winding end opening 220A is pulled out to the top. In this case, it is common to provide a shield ring 30 for mitigating the electric field at the lower end, but the six conductors are collectively connected to the inner layer 22.
1 to the outer diameter side layer 222, the gap D becomes large at the - portion of the transition portion. Moreover, FIG. 7 is a principle explanatory diagram when the tap winding 22 of the structure shown in FIGS. 2 and 3 is made up of one layer. It is a modeling diagram in which capacitances Cc are connected.

The opening is the equivalent circuit diagram, R is the resistance of the wire conductor, and the parallel circuit of the resistance and the capacitance Cc between the wire conductors is equivalent to the number of wire conductors, that is, the total number of turns of the tap winding 22. will be connected in series.

Next, FIG. 8 is an explanatory diagram of the principle of the tap winding shown in FIGS. , is a modeling diagram in which the interlayer capacitances CL of each strand conductor between layers on the outer diameter side are connected together, and is an equivalent circuit diagram. One end of this tap winding 22 is connected to the medium voltage line terminal u, so when a strong voltage is applied to the medium voltage line terminal u during operation or testing of the transformer, one end of the tap winding 22 is also connected to the medium voltage line terminal u. At the same time, an impact voltage will be applied. In this case, the impact voltage itself has a very high frequency, and the potential distribution within the tap winding 22 is determined by the capacitance since the resistance is independent of frequency. As a result, the maximum voltage generated between the taps at both ends of the tap winding 22, that is, the terminals shown in FIGS. 7 and 8, is expressed by the following equation (1) in the structure shown in FIG.

n where ω: impulse voltage frequency n: total number of turns of the tap coil Further, in FIG. 8, if the total number of turns of the tap coil is the same as in FIG. 7, it is expressed by equation (2).

When comparing the magnitude of V1 and V2, the denominator of equation (2) is ω
Considering that NCL/2 is larger, 1>2, and the maximum voltage generated between taps can be suppressed to a smaller value with the structures shown in Figures 4 and 5 than with the structures shown in Figures 2 and 3. As a result, the insulation of tap windings and tap changers can be reduced.

However, in the windings shown in FIGS. 4 and 5, as shown in FIG. 6, each conductor is passed from the inner layer to the outer layer, so the gap d1 becomes large at the transition portion. However, there is a drawback that electric field concentration occurs and partial breakdown of the insulation occurs. The first object of the present invention is to reduce the gap in the transition portion from the inner layer to the outer layer of each of the plurality of conductors forming the tap winding, thereby preventing dielectric breakdown due to electric field concentration. A second object of the present invention is to provide a transformer winding that facilitates the connection work between the winding start and winding ends of a plurality of conductors, and also facilitates insulation and improves reliability.

The present invention comprises a plurality of windings concentrically wound on the outside of an iron core, at least one of these windings is a tap winding, and at least one or more windings are wound outside the tap winding. The tap winding has an inner layer formed by arranging multiple conductors in the axial direction and winding them into a cylindrical shape, and an inner layer formed by folding back the multiple conductors at the end. When the tap winding is formed from an outer diameter layer that is wound in a cylindrical shape on the outer diameter side, and the winding start and end windings are pulled out from the same end side, the tap winding is A plurality of Z eggs'. ′；．．
：ー[MeA：Medium：= Form the conductor by crossing it, and place the inner diameter side layer one by one at the folded part so that the winding start and winding ends of each conductor have the same potential facing each other. It is formed so as to extend to the layer on the outer diameter side.

An embodiment of the transformer winding of the present invention will be described below with reference to FIG. The six winding openings are placed in parallel in the axial direction from the upper part as the winding start opening 220, and the inner diameter side layer 221 is wound, divided into three parts at the transition part at the lower end, and the winding is sequentially shifted two by two in the winding circumferential direction. It is then wound upward as the outer diameter side layer 222.

By shifting in this way, the gap D2 at the end is
d1 in the conventional case of FIG. 6 can be reduced to 1/3. Therefore, the electric field in this gap portion can be relaxed and dielectric breakdown can be prevented. FIGS. 10 and 11 show another embodiment, in which six winding start guides 220 are inserted in parallel in the axial direction from the upper part, and the inner diameter side layer 22
1 is wound, and at the transition portion at the lower end, each wire is divided into six turns and is sequentially shifted in the winding circumferential direction, so as to pass over the outer diameter side layer 222.

Therefore, the gap D3 at the end is equivalent to one conductor, which is half of that in the above embodiment. The outer diameter side layer 222 includes the openings 12, 13, which are located in order from the top in the inner diameter side layer 221.
14, 15, 16, and 17 are inverted and positioned so that the order from the top is 18, 17A<16A, 15A, 14A, 13A. The so-called transposition in the winding axial direction is performed, and then the outer diameter side is wound in the winding axial direction up to the upper end. By shifting both the winding start lead 220 and the winding end lead 220A by one conductor in the winding circumferential direction at the top end lead connection, the lead connection of the tap winding can be made as shown in FIG. It is convenient to connect like
Each lead of the conductors to be connected is 13-13A,
14-14A, 15-15A, 16-16A, 17-1
7A, and by arranging them facing each other in this way, the connection work can be facilitated. Furthermore, since the opposing lead conductors are at the same potential, it is possible to improve the reliability of the lead part, which is likely to cause defects in the insulation of the winding. Although the above embodiment has been described in the case of an autotransformer, similar effects can be obtained even when applied to other general transformers.

As described above, the transformer winding of the present invention can reduce the gap in the transition portion from the inner layer to the outer layer of each of the plurality of conductors forming the tap winding, so that dielectric breakdown due to electric field concentration can be reduced. This has the effect of preventing

Further, it has the effect of facilitating the connection work of the winding start and winding ends of each conductor of the tap winding, as well as facilitating insulation and improving the reliability of the lead portion.

[Brief explanation of the drawing]

Figure 1 is a wiring diagram of a conventional autotransformer that keeps the medium voltage constant and switches the high voltage, Figure 2 is a cross-sectional view of a part of the transformer in Figure 1, and Figure 3 is Figure 2 is a single-line diagram of a transformer, and Figure 4 is a part of a single-wire transformer in which a conventional tap winding is formed with an inner winding layer and an outer winding layer, and an outlet is provided at the top. A cross-sectional view, Figure 5 is a single line diagram of the transformer in Figure 4,
Figure 6A is an explanatory diagram of the winding of the tap winding in Figure 4, the mouth is a sectional view taken in the direction of Figure 7, and Figure 7 is a diagram explaining the principle when the tap winding in Figure 2 is composed of one layer. Figure 8 is the principle for the tap winding shown in Figure 4. A is a modeling diagram that connects the strand conductors and the inter-strand capacitance between them, and the inter-layer capacitance of each strand conductor between the opposing inner and outer diameter layers. Figure 9A is an explanatory diagram of tap winding showing an embodiment of the transformer winding of the present invention.
10 is a winding explanatory diagram of a tap winding showing another embodiment of the transformer winding of the present invention. FIG. 11 is a sectional view taken along the line M-X in FIG. The figure is a wiring diagram of the tap winding shown in FIGS. 9 and 10. 12, 13, 13A, 14, 14A, 15, 15A, 1
6, 16A, 17, 1TA, 18... meddling,
20...Iron core, 21...Series winding, 2
2... Tap winding, 23... Shunt winding, 24... Tertiary winding, 220... Winding start opening, 220A... ...Interference at the end of the volume, 221
...Inner diameter side layer, 222......Outer diameter side layer.

Claims (1)

[Scope of Claims] 1. A device comprising a plurality of windings concentrically wound on the outside of an iron core, at least one of these windings being a tap winding, and at least one winding outside the tap winding. The tap winding is formed by arranging a plurality of conductors in the axial direction and winding them in a cylindrical shape to form an inner diameter side layer, and by folding back the plurality of conductors at the end to form an outer diameter of the inner diameter side layer. The tap winding is formed from an outer diameter layer formed by winding in a cylindrical shape on the side, and the tap winding has a winding start opening and a winding end opening drawn out from the same end side, and the tap winding has an inner diameter side layer and an outer diameter side layer. dividing each of the plurality of conductors into at least two parts at the folded part with the radial side layer;
A transformer winding characterized in that each of these layers is sequentially shifted in the circumferential direction of the winding to extend from the inner layer to the outer layer. 2.Equipped with a plurality of windings concentrically wound on the outside of the iron core, at least one of these windings is a tap winding, and at least one winding is arranged outside the tap winding. , the tap winding is formed by arranging a plurality of conductors in the axial direction and winding them into a cylindrical shape, forming an inner diameter layer, and folding the plurality of conductors at the ends to form a cylindrical outer diameter side of the inner diameter layer. The tap winding is formed from an outer diameter layer formed by turning, and the tap winding has a winding start opening and a winding end opening drawn out from the same end side, and the tap winding has an inner diameter layer and an outer diameter side layer. At the folded part, each of the plurality of conductors is
The transformer is formed by shifting each conductor in order from the inner diameter layer to the outer diameter layer, and the winding start lead and winding end lead of each conductor are arranged so that the same potentials are opposed to each other. device winding.