JPS6342402B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to the construction of a large current winding for a transformer, and in particular to a cylindrical structure in which a plurality of transposed conductors are wound spirally along the cylindrical surface as parallel conductors. Related to winding.

[Prior art and its problems]

In high-current windings of transformers, the cross-sectional area of the conductor becomes large, making winding work difficult and increasing eddy current loss. Therefore, the transposed conductor 1 shown in Figure 1 is generally used. has been done. This transposed conductor 1 is a collection of many parallel strands 2 with thin strand insulation, arranged in two rows above and below as shown in the figure, and this arrangement of parallel strands 2 is sequentially transposed at a predetermined pitch. The assembled parallel strands are bound together by a common insulator 3. When winding this transposed conductor, the vertical direction shown in the figure is the axial direction of the winding. Therefore, the axial dimension of the parallel strands is determined from the viewpoint of suppressing eddy current loss, and the radial dimension is There are restrictions on the current carrying cross-sectional area of a single transposed conductor made up of these parallel strands, which are limited in terms of bending process limits. Therefore, when constructing a large current winding, it is necessary to use several transposed conductors in parallel.

In this case, conventionally, all the parallel conductors are wound in a helical winding arranged one on top of the other in the radial direction, or as a cylindrical winding in which all the parallel conductors are arranged and wound in the axial direction as shown in A to F in Fig. 2. It was used. However, helical windings have the disadvantage of having many dislocation points in order to flow a balanced current through each conductor, which increases the number of man-hours. On the other hand, with cylindrical windings, when the number of parallel conductors increases, each conductor is affected by leakage magnetic fields in the radial direction of the ends. In addition to problems such as unbalanced currents occurring between parallel conductors, there were also the following problems with cooling.

That is, in the conventional cylindrical winding, the cooling surfaces are both the left and right sides, and since there are conductors above and below, there is almost no heat radiation to the upper and lower surfaces. As mentioned earlier, a transposed conductor is a collection of thinly insulated strands, and as is well known, electrical insulators not only exhibit high resistance to heat conduction, but also exhibit high resistance to heat conduction at the contact surfaces of the strands. Because of the resistance, in order for the heat generated in the central strand of the conductor to radiate from the sides through many thermal insulations, a much larger temperature difference is required compared to a conductor made of one strand. In the solid line in Figure 3, which shows the temperature distribution inside the conductor, the temperature difference θ ₁ between the center and both sides becomes very large, and even if the average temperature is within the standard value, the maximum value is much higher than the expected value. This resulted in an unfavorable effect on the life of the insulator. For this reason, in the past, it was unavoidable to take uneconomical measures such as lowering the current density or increasing the circulation speed of a cooling medium such as insulating oil to increase cooling efficiency.

[Purpose of the invention]

The present invention was made in view of this point, and provides a multi-parallel cylindrical winding in which the temperature rise of the winding is reduced by cooling the transposed conductor from three sides, and the volume of the winding portion including the cooling passage does not increase. The purpose is to

[Key points of the invention]

According to the present invention, in a cylindrical winding in which a plurality of parallel conductors are wound spirally along a cylindrical surface, the parallel conductors forming one turn are arranged in two transposed conductor layers in the radial direction. This is achieved by arranging a plurality of transposed conductors in the direction of the winding axis, and providing radial cooling passages between the transposed conductors in the parallel windings.

The reduced axial coolant passages due to the overlapping winding of the two transposed conductors can be taken up as radial coolant passages to provide three cooling surfaces per transposed conductor. The radial cooling passage can be shared by the objects placed above and below it, so if the cross section of the transposed conductor is square, the volume required for the new radial cooling passage will be the same as that of the old axial cooling passage. Corresponds to that which has decreased. By cooling from three sides, the temperature difference θ ₁ within the transposed conductor shown in Figure 3 decreases, making it possible to increase the current density compared to the old one, and thereby making the winding smaller. . Dislocated conductors, which have a large cross-sectional area in order to conduct large currents, have a shape as shown in Figure 1, where the radial dimension is larger than the axial dimension due to the eddy current restriction mentioned at the beginning. As a result of the provision of the cooling body passages, the cooling effect is increased and the cross-sectional area of the dislocation conductor can be reduced, thus defeating the purpose of the present invention, which is to prevent the volume of the winding portion including the cooling body passages from increasing. There isn't.

It is particularly advantageous to apply this configuration when the number of turns of the winding is large and therefore the winding is arranged in several layers. The overlapping winding of the two transposed conductors increases the number of turns that can be accommodated in the axial direction of the winding, thereby reducing the total number of interlayer insulation and making effective use of the volume occupied by it. It is from.

Since two of the parallel conductors are wound overlappingly, these two must undergo transposition, but on the other hand, the number of conductors arranged in the winding axis direction is halved, and the unbalanced current due to leakage magnetic field is reduced. In consideration of loss and temperature rise, the increase in winding man-hours can be kept to a minimum by performing transposition every few turns.

[Embodiments of the invention]

FIG. 4 shows an embodiment of the present invention in a schematic cross-sectional view along the axial direction of the winding, in which parallel conductors constitute one turn by six transposed conductors 1 indicated by A to F. is formed. The transposed conductors indicated by A and B, C and D, and E and F are each wound in layers to form a conductor row 41, and a duct (not shown) is inserted between each conductor row 41. The windings are arranged in three rows across the formed radial cooling body passage 42, and are wound in a spiral shape along the cylindrical surface as a whole. Radial heat sink channels are also provided between one turn and the next, in which transpositions can take place if necessary. The layer 43 wound in a predetermined number of turns connects the axial cooling body passage 44, the interlayer insulating tube 4, and the axial cooling body passage 4 again.
4 and is concentrically opposed to another layer 45. In this case, the axial arrangement order of the conductor rows 41 arranged in three rows is reversed at a location extending from the end of the cylindrical winding of one layer 43 to the end of the cylindrical winding of the adjacent layer 45. The left-hand side of the layer 43 and the right-hand side of the layer 45 respectively serve as axial cooling passages, and all the dislocation conductors are cooled from three sides.

〔Effect of the invention〕

According to this invention, since the three surfaces of the dislocation conductor can be used as cooling surfaces, the temperature difference θ ₂ between the center and side portions is reduced to the temperature of the highest temperature portion in the center, as shown by the dotted line in Figure 3.
t ₂ is also significantly lower, so that an economical transformer can be obtained. Furthermore, the axial dimensions of the end conductors A to F are reduced, thus reducing unbalanced currents between the parallel conductors due to radial leakage fields. When the number of turns of this winding is large, the number of interlayer insulators is reduced compared to conventional cylindrical windings, so the occupied volume can be effectively used to increase the cooling effect, and the winding and the entire transformer are Since it can be downsized, it is particularly useful when applied to large capacity capacitors.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a transposed conductor, Fig. 2 is a schematic diagram of the structure of a conventional cylindrical winding, and Fig. 3 is a temperature distribution diagram with respect to the radial position of the cylindrical winding, where the solid line is the conventional one and the dotted line is the invention. FIG. 4 is a structural diagram of a two-layer cylindrical winding, with two wires stacked and three wires in parallel, according to an embodiment of the present invention. 1: Dislocation conductor, 41: Conductor row, 42, 44: Cooling body passage, 43, 45: Layer.

Claims (1)

[Claims] 1 In a cylindrical winding in which multiple transposed conductors are wound spirally along the cylindrical surface as parallel conductors, 1
The parallel conductors forming the turns are arranged in the radial direction as two overlapping transposed conductors and in the axial direction as a plurality of parallel windings, and a cooling body passage is provided in the radial direction between the transposed conductors in the parallel windings. A cylindrical winding wire characterized by: