KR101800196B1 - Insert for a transformer coil, coil comprising such an insert, active portion and transformer comprising such an active portion - Google Patents

Abstract

The insert 20 for isolating the two windings included in the coils of the present invention comprises an entirely annular plate 21 and at least one of the surfaces of the plate 21 to form a channel for the flow of insulating fluid. And a plurality of spacers 31-36 disposed on the substrate. The plate 21 and the spacers 31-36 are made of polyaramid. The so-called main spacers 31-34 form at least one main channel 51-53 and the or each main channel 51-53 has two opposing sides of the plate 21, And extends in the main direction (Y23-Y24) connecting the corners 23, 24. The main spacers 31-34 are integral spacers and extend over a length L31, L32, L33, L34 of 40% or more of the length L21 of the plate 21, As shown in FIG.

Description

FIELD OF THE INVENTION [0001] The present invention relates to an insert for a transformer coil, a coil including the insert, an active portion, and a transformer including such an active portion. BACKGROUND OF THE INVENTION [0002]

The present invention relates to an insert for isolating two helical conductor windings included in a traction transformer coil. The present invention also relates to a traction transformer coil comprising at least one such insert. The present invention also relates to a traction transformer active portion comprising at least one such coil. The present invention also relates to a traction transformer comprising such an active part.

The present invention may be used in the area of a traction transformer provided in an electric energy vehicle such as a train, a light rail, a subway.

Traction transformer coils generally include a series of helical conductor windings, so-called "wafers, " and multiple inserts, so-called" screen washer. &Quot; The windings and the inserts overlap in a folded and coaxial manner. Each insert generally serves to cool, support, and electrically isolate the two windings superimposed on the insert.

US-A-3 602 858 relates to an electric induction device of the transformer type. The transformer includes windings of several coils spaced axially, with isolated washers arranged between the coils. The spacers are arranged between the isolated washers and adjacent components to form a cooling duct.

In a known manner, prior art inserts generally include a plate and a plurality of spacers arranged on the surface of the plate. The plates and spacers may be made of polyaramid, which is a material having appropriate mechanical behavior, electrical resistance, and thermal stress resistance. These inserts have a plurality of small spacers spaced from one another to form a passageway for the flow of insulating fluid. The manufacture of such inserts is time consuming and complicated, which is costly because each of the plurality of spacers must be located in the correct position to perform the support and cooling functions.

In particular, the present invention seeks to solve these shortcomings by providing easy and optimized cooling, mechanical support and electrical isolation.

To this end, the present invention relates to an insert for isolating two conductive helical windings included in a traction transformer coil, said insert comprising at least one plate and a plurality of spacers, said at least one plate having a generally annular Wherein the spacers are disposed on a surface of at least one of the surfaces of the plate to form a channel for flow of the insulative fluid and wherein the plates and spacers are wholly or partly formed of polyamide, preferably Nomex < RTI ID = 0.0 > . The insert is so-called main spacers form at least one main channel, the or each main channel extending in a main direction connecting two opposing edges of the plate through a plurality of directional changes, the main spacers being integral spacers Characterized in that it extends over a length of at least 40% of the length of the plate and said length is measured parallel to the main direction.

In other words, the major spacers are longer than the dimensions of the plate, which limits the number of spacers required to perform the support, cooling, and isolation functions. Thus, the insert according to the invention is simpler and less expensive to manufacture.

Other advantageous but optional features of the present invention are considered in accordance with all technically possible combinations or independently.

The main spacers extend over a length of at least 70% of the length of the plate.

The main spacers are secured to the plate using ultrasonic welds made of polyaramid.

The spacers have straight segments in the opposite corner region of the plate.

The surface area occupied by the spacers arranged on one surface of the plate is no more than 50%, preferably no more than 40%, more preferably no more than 35% of the surface area of said surface of the plate.

The spacers are arranged to define the edges of the plate extending parallel to the sealed main direction relative to the insulating fluid.

- The insert contains several main channels.

The main spacers form the or each main channel with a periodic functional shape.

The periodic functional shape is selected from the group consisting of zigzag, saw blade, sine wave, and slot.

The plate includes a tamper-proof mechanism, such as a notch, orifice, or protrusion, to distinguish between the two surfaces of the plate during assembly of the insert within the traction transformer coil.

The invention also relates to a traction transformer coil comprising a series of helical conductor windings and a plurality of inserts as described above, wherein two consecutive windings are isolated by at least one insert, said windings and inserts being interchangeable and coaxial .

The present invention also relates to a pull transformer active portion comprising coaxially superimposed at least one low voltage coil and at least one high voltage coil, characterized in that at least one of the low voltage coil and the high voltage coil is the coil coil described above do.

The present invention also relates to a traction transformer in which a magnetic circuit surrounds a coil, said transformer comprising the active portion described above.

The main spacers forming the main channels of the insert according to the present invention are longer than the dimensions of the plate, thereby limiting the number of spacers required to perform the mechanical support, cooling, and electrical isolation functions. Thus, the insert according to the invention is simple and has a low manufacturing cost.

The active part according to the invention can be integrated in a "shell-type" transformer in which a traction transformer, in particular a magnetic circuit, surrounds the two coils. The coil and active part according to the invention comprising the insert according to the invention are not only inexpensive but reliable as the mechanical support, cooling and electrical isolation functions are effectively performed by the insert according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention and its advantages will be understood by the following detailed description with reference to the accompanying drawings, which are provided by way of non-limiting example only.
1 is a partial cross-sectional view of a transformer coil according to the present invention.
Fig. 2 is a front view of the insert according to the invention, taken along arrow II in Fig. 1, and in Fig. 2 the cutting plane of Fig. 1 is referred to by line II.
3 is an enlarged view of the detail part (III) of Fig.

The transformer active part according to the invention comprises at least one high voltage coil and one low voltage coil, at least one of which is according to the invention. 1 shows a part of a high-voltage coil 1. Fig.

As used herein, the terms "low voltage" and "high voltage" refer to voltage scales in a traction transformer in accordance with the present invention. For example, in the case of a traction transformer with an output power of approximately 1000 kVA, the undervoltage may typically include between 500V and 2000V, and the high voltage may typically comprise between 15kV and 30kV.

The coil 1 comprises a stack or series of windings 10 of conductors (not shown) wound diagonally. The coil 1 also comprises an insert 20 according to the invention. Since the two successive windings 10 are isolated by the at least one insert 20, the insert 20 is qualified as an insert, in this case being isolated by a single insert 20 in the example of Fig.

The axial ends of the coils 1 in the overlap direction X1-X'1 are formed by the isolating members 2, The windings 10 and the inserts 20 are superimposed in an alternating and coaxial manner, and the superimposing axes coalesce with or are parallel to the superposition direction X1-X'1. As used herein, the term "coaxial" refers to the overall symmetry axis of the insert 20 and the winding 10. In the examples of Figs. 1 and 2, this whole symmetry axis coalesces with the overlapping direction X1-X'1.

The insert 20 according to the invention comprises a plate 21 and a spacer, indicated generally at 30 in FIG. Spacers are sometimes also called "seams".

Figure 2 shows an insert 20 comprising a plate 21 and a set of spacers 30 with a portion of the spacers indicated as 31, 32, 33, 34, 35, 36 in Figures 2 and 3 do. A set of spacers 30 visible in FIG. 2 are disposed on a surface 211 of one of the surfaces of the plate 21. Another set of spacers, which are symmetrical to the set 30 with respect to the plate 21, are disposed on the other surface 212 of the plate 21, as shown in Fig. The profile of the windings 10 superimposed on the insert 20 is shown in broken lines in FIGS.

The spacers 31 to 36 are arranged on the plate 21 so as to form channels for the flow of insulating fluid, in particular the main channels 51, 52 and 53, seen in FIG. Such insulating fluid may be, for example, a synthetic ester of the Midel (R) type. The insulating fluid can cool the coil (1) by discharging the heat generated in the winding (10) when the transformer is in use. The insulating fluid also contributes to electrically isolating the two consecutive windings (10).

In the plate 21 and the set 30 of spacers, the spacers 31 to 36 are made entirely of polyaramid, especially Nomex (R). The mechanical behavior, electrical resistance, and thermal stress resistance of these polyaramids allow the insert 20 to perform mechanical support and electrical isolation functions with respect to the windings 10. The mechanical support function includes, among other things, minimizing the bending that occurs between the two spacers, for example against mechanical stresses occurring during a short circuit.

Conductors (not shown) forming the windings 10 are wound around the overlapping portions X1-X'1 as a whole flat spiral. Such conductors may comprise, for example, a polyurethane coating, for example a multi-stranded wire covered with Nomex (R). The coating can be done by taping the conductor.

The plate 21 has an annular shape as a whole. The central region of the plate 21 has a rectangular opening 22 for passage of a magnetic core (not shown). The outer peripheral portion of the plate 21 has an oblique corner and is entirely rectangular. Therefore, the outer peripheral portion of the plate 21 is more precisely an octagonal shape.

Among the spacer sets 30, there is a distinction between so-called main spacers 31, 32, 33, 34 and secondary spacers 35, 36. The main spacers 31 to 34 form three main channels 51, 52 and 53. Each main channel 51, 52 or 53 extends along a main direction Y23-Y24 connecting two opposing edges 23, 24 of the plate 21 through a plurality of directional changes. In the example of Fig. 2, the main directions (Y23-Y24) are parallel to the longest side of the rectangle formed by the maximum dimension of the plate 21, In other words, the main directions (Y23-Y24) are parallel to a large length of a rectangle defining the opening 22 or a rectangle in which the outer periphery of the plate 21 is fitted. Further, the main directions (Y23-Y24) are perpendicular to the overlap direction (X1-X'1).

More specifically, the main spacers 31 and 33 form the main channel 51, the main spacers 31 and 32 form the main channel 52 therebetween, and the main spacers 32 and 34 form The main channel 53 is formed.

In this way, the spacers, in particular the spacers 31 to 36, form channels for the flow of insulating fluid for discharging the heat generated in the winding 10, in particular the main channels 51, 52 and 53 So that it contributes to performing the cooling function of the coil 1. [ Spacers 31 to 36 also contribute to performing the support function by transmitting the force exerted by the winding 10 to form a magnetic field in the plate 20. [ In addition, the dimensions of the spacers, the insulating fluid, and the plate 21 make it possible to electrically isolate two consecutive windings 10.

In order to cause a plurality of directional changes of each main channel 51, 52 or 53, the main spacers 31 to 34 preferably each have a periodic functional shape. More specifically, the edges of the spacers 31 to 34 have a periodic functional shape. In this way, the main spacers 31 and 32 have a zigzag shape, and the spacers 33 and 34 have a slot shape.

The periodic functional shape may be selected from the group consisting of zigzag, saw blade, sine wave, and slot. This periodic functional shape makes it possible to form the main channels 51, 52 and 53 along the main direction (Y23-Y24) and exhibiting a large number of directional changes in most of the individual lengths.

In the region of the edges 23 and 24, the spacers 31 to 36 have straight segments. These straight segments enable the collection and release of the insulating fluid without causing excessive pressure loss.

Each of the main spacers 31 to 34 is a one-piece spacer and is not less than 40% of the length L21 of the plate 21, which is a length measured parallel to the main direction (Y23-Y24) (L31, L32, L33 or L34) which is preferably at least 70%.

The length L21 may be, for example, approximately 1000 mm. The maximum width of the plate 21 measured perpendicularly to the main directions (Y23-Y24) may be, for example, approximately 1000 mm. In the examples of FIGS. 2 and 3, the lengths L31, L32, L33 and L34 are approximately 786 mm, 976 mm, 571 mm and 476 mm, respectively, which are 79%, 98%, 57% .

By making the main spacers 31 to 34 into a single piece, it is simplified to fix them to the plate 21. [ In fact, the spacers 31 to 36 can be fixed to the plate 21 using ultrasonic welds made of polyaramid. Considering that the set of spacers 30, in particular the main spacers 31 to 36, are correctly located, by assembling them integrally, the assembly time of the spacers with respect to the plate 21 and hence the cost of the insert 20 .

As used herein, the term "single-piece" refers to a component in which at least one of the dimensions is integral. For example, the main spacer is a single piece along the longitudinal direction, that is, along the main direction (Y23-Y24).

The surface area occupied by all the spacers disposed on the surface 211 of the plate 21 is less than 50%, preferably less than 40%, more preferably less than 35% of the total surface area of the surface 211, Or less. As shown in FIG. 2, the surface area represented by "occupied" by the spacer on surface 211 is shown in white. Conversely, unoccupied or "free" surface areas by the spacers on the surface 211 are shown in gray in Figs. 2 and 3. The unoccupied or "free" surface area of the surface 211 corresponds to the circulation of the insulating fluid. In the example of Figures 2 and 3, the ratio of the "occupied" surface area to the total surface area of the plate 21 is approximately 30%. This ratio makes it possible to find an optimal compromise between the mechanical support and cooling functions performed by the insert 20. [

The spacers 33 and 34 are disposed on the plate 21 to seal the edges 25 and 26 of the plate 21 extending parallel to the main direction Y23 to Y24 against the insulating fluid. In this manner, the insulating fluid flows from the edge 24 toward the edge 23 without leakage through the corners 25, 26, thereby ensuring a relatively uniform cooling of the plate 21. [

Similarly, to minimize bending of the winding 10 between two consecutive spacers, isolating two successive spacers 31, 32 measured parallel or perpendicular to the main direction (Y23-Y24) The maximum distance is 70 mm or less, preferably 50 mm or less. As shown in Fig. 2, this maximum distance for isolating two consecutive spacers is the distance (L31.32) measured parallel to the main direction (Y23-24) or measured perpendicular to the main direction (Y23-Y24) (H31.32). ≪ / RTI >

In addition, the outer peripheral portion of the plate 21 includes a notch 27 that performs a mistake prevention function. This prevents the manufacturing cost of the insert from being reduced while the operator is assembling the insert 20 between the coil 1 of the transformer according to the invention and the two windings 10, This is because it is possible to quickly distinguish between the two surfaces 211 and 212. Thus, such a mistake prevention mechanism reduces the risk of errors during assembly.

According to an alternative embodiment, which is not shown, the error preventing mechanism can be formed by the projecting portion or the orifice.

The insert 20 serves to cool the windings 10, mechanically support them, and electrically isolate them from each other. By making the components of the insert 20 from polyamide, preferably Nomex (R), it becomes possible to withstand higher temperatures than conventional materials such as cardboard.

According to an alternative arrangement not shown, the insert according to the invention comprises a single main channel.

The main spacers forming the main channels of the insert according to the present invention are longer than the dimensions of the plate, thereby limiting the number of spacers required to perform the mechanical support, cooling, and electrical isolation functions. Thus, the insert according to the invention is simple and has a low manufacturing cost.

The active part according to the invention can be integrated in a "shell-type" transformer in which a traction transformer, in particular a magnetic circuit, surrounds the two coils. The coil and active part according to the invention comprising the insert according to the invention are not only inexpensive but reliable as the mechanical support, cooling and electrical isolation functions are effectively performed by the insert according to the invention.

1: coil, 2, 3: isolating member,
10: winding 20: insert
21: plate 211, 212: surface
22: openings 23, 24, 25, 26: corners
27: notch 30: set of spacers
31, 32, 33, 34, 35, 36: spacers
51, 52, 53: main channel

Claims (17)

An insert (20) for isolating two conductor spiral windings (10) included in a traction transformer coil (1), said insert (20) comprising at least one plate (21) and a plurality of spacers (31-36) Wherein the at least one plate has an annular overall shape and the spacers are electrically connected to the surfaces of the plates and to the surfaces of the plates, , The plate (21) and the spacers (31-36) being an insert (20) made entirely or partly of polyaramid,
The so-called main spacers 31-34 form at least one main channel 51-53 and the or each main channel 51-53 has two opposing sides of the plate 21, Extends in the main direction (Y23-Y24) connecting the edges (23, 24)
The main spacers 31-34 are integral spacers and extend over a length L31, L32, L33, L34 of 40% or more of the length L1 of the plate 21, Is measured in parallel with the insert. 2. Insert according to claim 1, characterized in that the main spacers (31-34) extend over a length (L31, L32, L33, L34) of at least 70% of the length (L21) of the plate (21). 3. Insert according to claim 1 or 2, characterized in that the main spacers (31-34) are fixed to the plate (21) using ultrasonic welds made of polyaramid. 3. Inserts according to claim 1 or 2, characterized in that the spacers (31-36) have straight segments in the area of the opposed edges (23, 24) of the plate (21). A surface area occupied by spacers (31-36) disposed on one surface (211) of the plate (21) Wherein the surface area is less than 50% of the surface area. 3. A method as claimed in claim 1 or 2, wherein the spacers (33, 34) form edges (25, 26) of the plate (21) extending parallel to the main direction (Y23-Y24) Of the insert. 3. Insert according to claim 1 or 2, comprising several main channels (51-53). 3. Insert according to claim 1 or 2, characterized in that the main spacers (31-34) form the or each main channel (51-53) with a periodic functional shape. 9. The insert of claim 8, wherein the periodic functional shape is selected from the group consisting of zigzags, saw blades, sine waves, and slots. The plate according to any one of the preceding claims, characterized in that the plate (21) is made to prevent accidental deflection during the assembly of the insert (20) in the traction transformer coil (1) And an instrument (27). 11. The insert of claim 10, wherein the error prevention mechanism (27) is a notch, orifice or protrusion. 2. Insert according to claim 1, characterized in that the plate (21) and the spacers (31-36) are wholly or partly made of Nomex (R). 2. A method according to claim 1 wherein the surface area occupied by the spacers (31-36) disposed on one surface (211) of the plate (21) %. ≪ / RTI > 6. The method of claim 5 wherein the surface area occupied by spacers (31-36) disposed on one surface (211) of the plate (21) is less than 35% of the surface area of the surface (211) %. ≪ / RTI > A traction transformer coil (1) comprising a series of helical conductor windings (10) and a plurality of inserts (20) according to any one of claims 1 to 3, characterized in that two consecutive windings Is insulated by an insert (20) of the winding (10) and the insert (20) are overlapped in an alternating and coaxial manner (X1-X'1). At least one of the low voltage coil and the high voltage coil (1) being a traction transformer coil according to claim 15, characterized in that it is a traction transformer active part comprising at least one coaxially superimposed low voltage coil and at least one high voltage coil Features a traction transformer active part. A traction transformer in which the magnetic circuit surrounds the coil (1), comprising a traction transformer active part according to claim 16.

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