FI115869B - Disc Winding - Google Patents

Description

1,115,869

A disc winding

BACKGROUND OF THE INVENTION

The invention relates to a flange end 5 of a large or distribution transformer or a choke consisting of two or more parallel sub-conductors or double cables.

Because of the ease of bending of the conductor and to reduce eddy currents, the power transformer coil conductor typically consists of a plurality of parallel flat copper or aluminum conductors instead of one large rectangular conductor. Each sub-conductor is insulated from its surface, allowing a potential difference between two adjacent sub-conductors, thus preventing the formation of a vortex current between the conductors.

Still, there are serious problems with the winding. The length of the parallel sub conductors is different because the average distance to the core of the transformer 15 is different. Therefore, a different voltage is induced in the sub-conductors and because they are galvanically connected at both ends, a coil current is present in the coil which heats the coil. The load current is also unevenly distributed between the sub-conductors, reducing the overall load capacity. Two major solutions are known to avoid these problems.

20 A very traditional winding structure is one in which there is a mirror-image alternate cruise between each of the two adjacent flanges, with each one! * *. a separate sub-conductor for each cruise is bent separately.

Due to the inhomogeneity of the magnetic field, various alternate cruise arrangements are used, some of which are disclosed in 25 JP 1246807. The use of four parallel sub conductors is shown in which the coil is divided into two blocks, the middle cruise being implemented in two groups of two * mirror image switching cruises.

• · The problem with these solutions is that a large number of discrete '; · 30 sub-conductors must be bent manually and carefully insulated.

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Typically, an additional insulating strip is wrapped around the sub conductor, and a piece of insulating board is arranged to be mounted between the two conductors to prevent short-circuiting. The optimized cruise location must be calculated using a special computer program. In general, labor costs are the biggest problem, but also the long lead time in production.

Another solution is to use Continuous Transposed Cable (CTC). The prefabricated cable consists of parallel sub-conductors alternated and twisted into a cable. The flange winding is wound from this cable and cruises can be done by bending the cable 10, for example with a pneumatic press tool. This method reduces the winding working time because you do not have to take alternate cruises.

The problem with CTC cable is its high acquisition cost and long delivery time, as it only has a few main suppliers and has to be individually designed for each type of transformer. In addition, the tap-off connection is more difficult than with normal separate sub conductors.

Typically, the dimensions of large power transformer sub-conductors cannot be standardized but are optimized on a case-by-case basis based on material costs and long-term energy losses.

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BRIEF DESCRIPTION OF THE INVENTION

20th The object of the invention is to provide a flange winding having the above. : These issues have been resolved. This is achieved as defined in independent claim 1. Preferred embodiments are described in the dependent claims.

The invention is based on a flange winding which is axially divided into a plurality of sections, each type of cruise being of the type:. . where all the sub-conductors are bent substantially parallel. Alternating Cruises: "': between two parallel flanges balances the current and voltage of the sub-conductors. Preferably, the coil is divided into as many axial blocks as, ·,: 30 which is the number of parallel copper or aluminum conductors in the conductor. good balance but at the same time the minimum number of alternate cruises 115869 3. Alternatively, the number of coil blocks is a multiple of the number of sub-wires, which gives a good balance of up to three parallel sub-wires. A two-block solution can be used if the number of sub-conductors is not too large, preferably two or three, and the voltage and current requirements of the coil are not important criteria. at the same time, instead of bending each individual sub-conductor individually, the working time is dramatically reduced. 10 ti. The number of individual cruise bends, for example, with six parallel sub-conductors, can be reduced by more than 80% compared to a conventional winding arrangement.

Instead of measuring and positioning each sub-conductor, as in a traditional mirror-image alternating cruise on each flange, only one cruise needs to be measured and positioned in a parallel cruise. All parallel sub-conductors are bent substantially parallel in a single operation using, for example, a pneumatic press tool or an electric hand tool.

| A Alternatively, the parallel cruise is on the outer or inner rim of the winding, but the alternate cruises may be on either the outer or inner periphery! depending on whether the number of flanges in the block is odd or even.

There are evidently several ways to make power and voltage balancing • »'alternating cruises between two flanges.

'·· * In the case of an even number of blocks and thus an odd number of alternate cruises, the mirror image type alternating cruise is used) I t:> t;' in the center of the winding to calculate the optimization calculations for the location of the cruise. '* Major unnecessary.

: The mechanical stress between the wires is kept to a minimum in a criss-crossing · ··· ”and the so-called Saxo phenomenon, which is inevitable in a 30-turn cruise, is avoided. Thus, there is no need for separate isolation of the sub-conductors: · A single post-insulation of the entire bundle is sufficient.

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Insulation board pieces are not needed between separate sub-conductors as required for mirror image alternation on a cruise. Only one piece of insulation board is needed to isolate the entire bunch from the previous round.

Of course, an additional strip of paper can be inserted between the parallel sub conductors to improve the insulation strength. If the bend is sufficiently stiff and thus the insulation of the conductors remains intact during bending, no additional insulation is normally required.

Because the so-called Saxo phenomenon is avoided between parallel sub-conductors, the risk of mechanical damage causing a short circuit is significantly reduced.

10 Coil cooling also improves because there are fewer obstacles to the flow of coolant in radial channels as the number of cruises decreases.

However, the idea of the invention is to make the majority of cruises simple to manufacture due to parallel bending and thus reduce the number of alternating cruises, thereby resulting in savings in manufacturing time.

15 BRIEF PRESENTATION OF THE PATTERNS

In the following, the invention will be described in more detail by way of example, with reference to the accompanying drawings, in which 'Figure 1 shows a coil-side cruise where all. : 20 sub-conductors are bent in parallel; • »: Figure 2 shows a detail of a parallel cruise over- * ·; '': With isolation means; Figure 3 shows a schematic view of a parallel cruise; • »:,. Figure 4 shows a principle view of a mirror image alternate cruise,

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; * · '. wherein each of the six sub-conductors is separately bent; »*«, · /: 30 Figure 5 shows a schematic view of an alternate cruise with six sub conductors bent in two groups; 5, 115069

Figure 6 shows an exemplary cruise diagram for six parallel sub-conductors of a flange winding according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a partial schematic view of a power transformer flange winding according to the invention. The flange winding consists of a conductor (1) wrapped around an insulating cylinder (2). The insulating rods (3) ensure axial flow of the coolant, but they are also arranged to position the insulating spacers (4). One flange (5) typically consists of a plurality of radial turns of the conductor (1) and is axially separated from the previous and subsequent flanges by means of discharge passages (4). According to the invention, within one section, the conductor (1) is always guided from one flange to another by folding it as a parallel cruise (6).

Figure 2 shows a detailed schematic diagram of the parallel cross-section (6). One conductor (1) consists of a plurality of substantially parallel sub-conductors (1a ... 1f). In a parallel cruise (6), all substantially parallel sub-wires (1a, .. 1f) are bent from the flange (5) to the next between two adjacent •: 20 insulating spacers (4).

'. The bending can advantageously be performed by pneumatic, hyd. : with roller or electric press tool in one step.

': In order to ensure an adequate level of insulation, the conductor (1) on the parallel cruise can be wrapped with an additional insulation strip (7) as one of the sub-conductors (1a, ·' ·: 25 ... 1f). In order to avoid the so-called "Saxony" phenomenon, where the insulation of the conductor (1) may be damaged, resulting in a short circuit, an additional insulation plate (8) may be arranged between two turns of the conductor (1).

t> t. ··. Figure 3 shows in principle how the conductor (1) is led to the plates I t shirt (5) for the next parallel cruise (6). All the parallel sub conductors 30 (1a, ... 1f) are smoothly bent from one flange to another together between the insulating spacers (4). Due to the plan view, only one sub-conductor (1a) can be seen in the drawing. Alternatively, the parallel cruise (6) is disposed on the outer or inner periphery of the flange (5).

The coil of the invention further comprises at least one type of alternate cruise shown in the drawings in Figures 4 or 5.

Fig. 4 shows the principle of the traditional game-picture rotation cruise (9), in which each individual sub-conductor (1a, ... 1f) is individually bent, one after the other, typically in adjacent spacings of the insulating spacer (4). In the coil of the invention, this type of alternation cruise is used as the middle alternation cruise in the event that an odd number of alternator-10 rolls occur.

Figure 5 shows a double-alternate cruise (10) in which the sub-conductors are bent in two groups. In Figure 5, by way of example, the six sub conductors (1a, ... 1f) are divided into two groups, two (1a, 1b) and four sub conductors (1c, ... 1f).

According to the invention, the distribution of sub-conductors between two groups may vary depending on the total number of sub-conductors. Typically, the power transformer has from one to eight sub conductors, but there may be more in the conductor (1).

· ': The solution of a single sub-conductor is not within the scope of the invention. Two sub conductors can only be divided in one way, into two groups of one sub conductor: one. The three sub conductors can be divided into one and two groups, or .. * vice versa. Four sub conductors for one and three or two and two, five sub conductors for one and four, two and three, six sub conductors for one and five, · ... · 'two and four groups. Seven sub-conductors in groups one and six, two and 25 in five, three and four, eight sub-conductors in one and seven, »*: · 'in two and six, three and five groups. Even a combination of different • »* ·; * 'Sois-alternate cruise on the same coil can be used.

Figure 6 shows an example of a cruise diagram of a flange winding for six sub-conductors (1a ... 1f). The winding consists of six blocks: V: 30, each block consisting of a plurality of flanges (5) not all of which are shown in the diagram. The parallel cruise (6) within the block maintains the mutual order of the sub-conductors (1a, ... 1f).

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Corresponding to six blocks of alternate cruises there are five. The middle alternation cruise (9) is a mirror image type in which each sub-conductor is bent separately and the order of the sub-conductors 1a, 1b, 1c, 1d, 1e, 1f is alternated in reverse order, i.e., 1f, 1e, 1d, 1c, 1b, 1a . The remainder of the Shift-5 Roller Cruises are double-shuttle cruises (10) with sub-conductors bent in two groups.

The most preferred embodiment of the arrays is such that the first array has two inner conductors and the second has all the remaining four sub conductors, or alternatively two outer and the remaining inner sub conductors. Thus, in the case of six sub-conductors, 10 conductors (1, ... 1f), the first group comprises two sub-conductors and the second group four. In the case of four sub conductors (1a, ... 1d), there are two sub conductors in each group. In the case of eight sub conductors (1a, ... 1h), the first group has two and the second group six sub conductors.

Fig. 6 shows, by way of example, how the two innermost sub-conductor groups at each double-alternate cruise (10) are moved outward and the other four sub-conductor groups inward, but the radial order of the sub-conductor pairs (1a, 1b), (1c, 1d) and ( 1e, 1f) remains.

The middle alternation cruise is the Mirror Alternate Cruise (9). An advantage of using this type of arrangement is that the number of flanges in the blocks can be arranged one to the other without the need for a power, lance optimization calculation.

• | . The number of flanges of the coil varies according to electrical requirements. In the exemplary case, the total number of flanges (5) is 96, there are six sub-conductors (1a, ..., 1f), each of the six blocks forming: · sixteen flanges (5). The number of blocks is the same as the number of

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**; the number of thimes.

!.: In the case of an even number of sub conductors, such as four, six, or: ..,: eight parallel sub conductors, the first group may also have only one sub conductor and the second three, five or seven, respectively. In this embodiment, all the alternate cruises are the same, the inner first group of sub-conductors being moved outward or vice versa 8115869 on each alternate cruise. No Mirror Alternate Cruise is required at all. With this embodiment, current balance calculations are required to determine the location of the cruises.

In an embodiment having an odd number of sub-conductors such as three, five, five, or seven, the double-alternate cruises (10) have an even number. In the case of three semiconductors, the wire is quite narrow in width and the power balance problems are smaller, so a fairly good result can be achieved without any optimization calculations. Balance problems become more significant with larger numbers of sub-conductors.

10 When using a dual cable, the middle mirror image alternate cruise (9) can be done simply by rotating the cable 180 degrees.

In distribution transformers, the insulating sleeve (2) is typically not used, but the coils are wound on a mandrel.

Typically, the transformer and its windings are in a position where the coolant flows horizontally between two flanges (5) delimited by two dielectric spacers (4) so that by bending all the sub conductors in parallel, most of the channels are left open and the coolant can flow freely.

• ««: Cruise charts and places for alternate cruises can be standardized for • »· 20 different sub-conductor numbers and it has been found that check calculations and - '· measurements are only needed during the application standardization phase.

, \ The voltage stresses between the conductors in the L1 test are lower due to the high capacitive coupling between the conductors. The high capacitance filters out the high frequency voltages between the conductors, and also the fact that: v, 25 the length of the sub conductors is the same between the ends of the coil does not cause any propagation between the conductors.

• * * 4 <, ·. According to the invention, a large number of separate cruises are reduced by a fraction of I *

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Compared to the traditional method of making a coil, the working time used for cruises is reduced. This results in reduced production time and cost savings. The invention makes it possible to increase the use of individual sub-conductors' * instead of the more expensive CTC cable in flanged coils, resulting in significant economic savings in material costs.

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The technical characteristics of the coils manufactured according to the invention are similar to those of conventionally manufactured coils.

Although only one embodiment has been described, it is to be understood that the present invention may be applied in various forms by one skilled in the art within the scope of the claims.

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Claims (3)

A disk winding in an induction transformer with concentric windings such as a power transformer or a distribution transformer or a concentric winding choke, wherein the conductor (1) consists of at least six parallel flat card conductors (1a) and the winding is axially divided into several sections, said number of sections is a multiple of the number of parallel conductor parts (1a), and each section comprises several disks (5) where each disk (5) is formed by several turns of conductors (1), the intersection of two axially adjacent sections being one cross-junction cruise (9, 10) and each cruise within a section is a parallel cruise (6) where the conductor parts are substantially curved in parallel, characterized in that at least one cross-junction cruise (10) where the conductor parts (1a, ... 1f) are curved into two groups and the middle cross-coupling cruise is a mirrored cross-coupling circuit icing (9). A sheet winding according to claim 1, characterized in that the number of sections is the same as the number of parallel conductor parts (1a, ... 1f). A sheet winding according to claim 1 or 2, characterized in that the first group consists of two conductor parts and the second group of the remnants of the above-mentioned conductor parts. 25