Electrical device having a tank with a bulging / convex portion

Abstract

To provide an electrical device (9) for connection to a high-voltage system comprising a tank filled with insulating fluid, which has at least one side wall (2), which forms a planar wall portion (3) and a radially outwardly curved bulging / convex portion (4), which increases the interior volume of the tank and extends between two axial edges (5, 6), and also comprising an active part, which is arranged in the tank and has a core (10) and at least one winding (7, 8) enclosing a portion of the core (10), and comprising at least one winding barrier system (11), which encloses one or more windings (7, 8), wherein the bulging / convex portion (4) is formed with a shape that complements a portion of the winding barrier system (11) and lies opposite it at a distance, such that the electrical device has increased dielectric strength, it is proposed that between the winding barrier system (11) and the bulging / convex portion (4) there is an additional barrier (13), which has a round portion (14), facing the bulging / convex portion (4) and bent radially outwards, and two planar flat portions (15, 16), which at an axial flange (17, 18) respectively extend out of the round portion (14) towards a free end.

Description

[0001] The invention relates to an electrical device for connection to a high-voltage network, comprising a vessel filled with insulating fluid, which has at least one side wall forming a flat wall section and a radially outwardly curved bulge section extending between two axial edges, increasing the internal volume of the vessel, an active part arranged in the vessel comprising a core and at least one winding enclosing a section of the core, and at least one winding barrier system enclosing one or more windings, wherein the bulge section is shaped to be complementary to a section of the winding barrier system and is located at a distance from it, wherein an additional barrier is arranged between the winding barrier system and the bulge section, comprising a circular section facing the bulge section and bent radially outwards, and two flat planar sections.which each extend from the circular section along an axial fold to a free end.

[0002] Such an electrical device is known from practice. For example, transformers have an active part that has a magnetizable core formed from iron sheets pressed together with their flat sides against each other. The core forms a closed magnetic circuit. The iron sheets are pressed together using a press frame. In three-phase active parts, the core forms, for example, three legs connected to each other by a lower and upper yoke. Each core leg is surrounded by an inner secondary winding and an outer primary winding. The core and these windings are arranged concentrically to each other. A transformer with a barrier that has both a round section and flat sections is known from JP S54 105731 A.As power and voltage increase, the active component grows larger, while the required transport dimensions of the boiler often have to be kept constant. For this reason, the distance between the active component and the boiler decreases. However, depending on the required operating voltage, this distance must not fall below a minimum distance.

[0003] To ensure this minimum distance, so-called bulged boilers are used, in which the boiler has side walls that form bulges. These bulges are located opposite the windings, so that the distance between the winding and the boiler wall does not fall below the required minimum distance. However, such bulged boilers have the disadvantage that high electric field strengths can develop due to the resulting corners at the transition between the bulged section and the flat section of the side wall.

[0004] The object of the invention is therefore to improve the reduction of the field in the edge area and thus avoid an electrical flashover.

[0005] The invention solves this problem by providing at least one adjuster that extends between the winding barrier system and the planar section of the additional barrier.

[0006] According to the invention, an additional barrier is arranged between the bulged section of the side wall to divide the free oil passage. The additional barrier has a rounded section that, like the bulged section, is bent radially outwards. On both sides of the rounded section, two flat sections are provided, each extending in a plane, so that a sharp bend, a fold, or in other words, a crease extending in the axial direction is formed between each flat section and the rounded section. This crease extends in the axial direction, whereas the rounded section, like the bulged section of the side wall, is bent radially outwards and thus has a rounded shape. The two flat sections of the additional barrier extend from the rounded section to their free end.

[0007] It has been found that an additional barrier designed according to the invention advantageously divides the free oil passage – particularly at the kinks in the side wall. Within the scope of the invention, an electrical device is thus provided whose active part can be designed for higher power outputs, i.e., higher voltages or higher currents, without having to deviate from the required transport dimensions.

[0008] The spacer, which can also be referred to as a standoff, is also made of pressed wood, cardboard or paper and serves to align the respective plan section of the additional barrier, whose free end could otherwise align freely.

[0009] The electrical device according to the invention is, for example, a transformer or an inductor. If the electrical device is a transformer, it has one or more pairs of inductively coupled windings. The two windings of a winding pair are, for example, arranged concentrically to each other, with one winding being a low-voltage winding and the other a high-voltage winding. A core leg extends through both windings as a core section.

[0010] The winding barrier system is advantageously formed from a series of barriers separated by oil channels, resulting in improved radial field attenuation. These barriers are made of particleboard. Such barrier systems are known to those skilled in the art, so a detailed description of their construction is unnecessary here. The barrier system preferably has a circular cylindrical outer contour. An additional barrier, advantageously made of an electrically non-conductive material such as particleboard, extends between these barriers. Alternatively, the additional barrier can also be made of paper or cardboard.

[0011] Advantageously, the round section is shaped to be complementary to the bulged section. According to this advantageous further development of the invention, the round section maintains a constant distance from the rounded, outwardly curved bulged section.

[0012] Further advantages arise when the planar sections extend parallel to the flat section of the side wall. With a parallel alignment of the planar sections to the flat section of the side wall of the electrical device according to the invention, the electric field is further subdivided at the edges of the side wall.

[0013] In a further advantageous embodiment of the invention, the additional barrier is held by means of at least one hinged segment arranged at a distance from the winding barrier system and by means of a retaining band arranged at a distance from both the winding barrier system and the bulged section. According to the invention, the additional barrier is held in place by means of a retaining band and cap segments. The cap segments, which are generally already installed in the boiler, are used to hold the additional barrier. The retaining band, which is designed, for example, as a flat band, extends around the additional barrier system so that, for example, its flat side rests against its outer contour. From there, it is wound around the rounded section of the additional barrier system, with suitable through-openings or slots being provided in the additional barrier.According to the invention, the retaining strap consists, for example, of cardboard, paper or another malleable pressed wood product.

[0014] The tensioner is conveniently attached to the winding barrier system via the retaining strap. Cords made of cardboard, paper, or another non-conductive material are used to attach it to the respective plan section, for example, to the free end of each plan section. The tensioner has suitable openings for this purpose. Each tensioner is provided with slots through which the retaining strap can be threaded.

[0015] Advantageously, the winding barrier system has a circular cylindrical outer contour, and the bulge section defines a portion of a circular hollow cylinder, with the winding barrier system and the bulge section being arranged concentrically to each other. As already explained above, the windings are cylindrical and arranged concentrically to each other and to the core leg they surround. According to this further development of the invention, this also applies to the winding barrier system, which, due to its complementary shape, then also affects the bulge section. This section is then a segment or portion of a circular cylinder.

[0016] According to a practical further development in this regard, the bulged section and the rounded section each define a section of a hollow cylinder, wherein the hollow cylinders have different radii and the bulged section and the rounded section are arranged concentrically to each other. According to this variant, what was stated above regarding the bulged section and the winding barrier system also applies to the rounded section and the bulged section.

[0017] It can also be advantageous if the two edges of the side wall, between which the bulged section extends, and the two folds of the additional barrier, between which the rounded section extends, form the same angle with respect to a common center point.

[0018] Further advantageous embodiments and benefits of the invention are the subject of the following description of exemplary embodiments of the invention with reference to the figures of the drawings, wherein the same reference numerals refer to identically functioning components and wherein Figure 1 shows a sectional top view of an electrical device according to the prior art, Figure 2 shows an embodiment of the electrical device according to the invention in a sectional top view, Figure 3 shows the attachment of the additional barrier to the winding barrier system, and Figure 4 shows the attachment of the cap segment and the segments of the winding barrier system in a perspective view.

[0019] Figure 1Figure 1 shows an embodiment of an electrical device 1 according to the prior art in a sectional view from above. The electrical device 1 shown is designed as a power transformer 1, which has a vessel filled with an insulating fluid, of which only one side wall 2 is visible. The side wall 2 has a flat wall section 3 and a radially outwardly convex section 4 that extends into the inner volume of the vessel. The convex section is arranged between two axial edges 5 and 6 extending in an axial direction. The axial direction extends in Figure 4 into the drawing plane or comes out of the drawing plane.

[0020] Within the tank, which is only partially shown with its side wall 2, a high-voltage winding 7 and a low-voltage winding 8 are arranged, which are arranged concentrically to each other and to a core leg which is not shown in the figure.

[0021] It is evident that the bulged section 4 is convex, increasing the internal volume of the tank, so that a required minimum distance is maintained between the high-voltage winding 7 and the side wall 2, thus preventing high electric field strengths and voltage flashovers inside the transformer 1. However, as already described above, high electric field strengths can occur at the edges shown as corners in the sectional view, so that the operating voltage of the power transformer cannot be increased further without voltage flashovers occurring at these corners or bends, which would irreparably damage the electrical device.

[0022] Figure 2Figure 1 shows an embodiment of the electrical device 9 according to the invention, which is again designed as a transformer 9. The transformer 9, only partially shown in a sectional top view, has a tank or boiler from which the Figure 2 Only one side wall 2 is shown, which again has a flat wall section 3 and a radially outwardly curved bulge section 4. The bulge section 4 extends between axially extending edges 5 and 6, which are in Figure 2 due to the chosen cropped representation, corners 5 and 6 are clearly indicated.

[0023] Transformer 9 is filled with an insulating fluid, for example a mineral oil or an ester liquid. Inside it is a magnetizable core, from which in Figure 2Only one core leg 10 is visible. The core leg 10 is concentrically enclosed by a low-voltage winding 8 and a high-voltage winding 7. The two windings 7 and 8 are in turn surrounded by a barrier system 11, which consists of individual radially spaced barriers 12. Oil channels are formed between the barriers 12 of the barrier system 11, which increase the electrical strength of the transformer 9.

[0024] Furthermore, an additional barrier 13 is discernible, which has a circular section 14 facing the bulged section 4, from which two flat sections 15 and 16 extend towards a free end. The circular section 14 is form-complementary to the circular cylindrical outer contour of the winding barrier system 11 and form-complementary to the bulged section 4 of the side wall 2. The flat sections 15 and 16 extend essentially parallel to the flat wall sections 3 of the side wall 2. In other words, the flat sections 15 and 16 extend from the axial folds 17 and 18, which are located in Figure 2 due to the two-dimensional representation, they are again depicted as corners.

[0025] In the Figure 2In the illustrated embodiment, the circular section 14 transitions into one of the planar sections 15 and 16 at the aforementioned axial folds 17 and 18. In other words, the additional barrier 13 is formed in one piece. In the illustrated embodiment, it consists of pressed wood, like the barriers 12 of the winding barrier system 11. However, other electrically non-conductive materials can also be used to manufacture the additional barrier. For example, the additional barrier can be made of cardboard, paper, or even an electrically non-conductive plastic.

[0026] Figure 3Figure 1 shows the attachment of the additional barrier 13 in more detail. It can be seen that it is held at a distance from the outer barrier 12 of the winding barrier system 11 by means of cap segments 19. The cap segments 19, which are also rounded, are L-shaped in a longitudinal section view and are clamped at their shorter base end by a lower fastening system 20. The fastening system 20 also serves to attach the barriers 12 of the winding barrier system 11 and is located here on the bottom of the tank. Longitudinal slots are formed between two adjacent cap segments 19, through which a planar section 16 of the additional barrier 13 extends.

[0027] In addition to the capping segments, a retaining band 21 is provided, which is made of cardboard and designed as a flat band. The retaining band rests with its flat side against the outer contour of the winding barrier system 11 and is guided from there through a slot 22 in the round section 14 of the additional barrier 13, so that the retaining band 21 surrounds the round section from the outside and thus provides additional support for the additional barrier 13.

[0028] Furthermore, a spacer or adjuster 22 is visible, which has an angled foot section 23 that rests against the outer contour of the winding barrier system 11. The retaining strap is guided over the foot section, so that the retaining strap 21 presses the foot section 23 against the winding barrier system 11. An adjuster slot 24 is formed in the lower area of ​​the adjuster 22, through which the retaining strap 21 is guided.

[0029] At the end of the adjuster 22 facing away from the foot section 23, through holes are provided, aligned with through holes in the planar section 16 of the additional barrier 13. A paper fastening cord 25 is guided through the through holes of the adjuster 22 and the through holes of the planar section 16, thus attaching the adjuster 22 to the planar section 16. According to the invention, the fastening cord can also be made of another electrically non-conductive material. The adjuster 22 is dimensionally stable, ensuring a firm and stable alignment of the planar sections 16 with the flat wall sections.

[0030] Figure 4The illustration shows the attachment of the cap segments 19 to the fastening system 20. In particular, the L-shaped design of the cap segments 19 is visible in longitudinal section. Furthermore, the inner barriers 12 of the winding barrier system 11 are visible due to the partially transparent representation.

Claims

1. An electric device (9) for connecting to a high voltage network, having - a tank filled with insulating fluid and having at least one side wall (2) forming a planar wall portion (3) and a radially convex bulging portion (4) that increases the internal volume of the tank and extends between two axial edges (5, 6), - an active part disposed in the tank that has a core (10) and at least one winding (7, 8) encompassing a portion of the core (10), and - at least one winding barrier system (11) encompassing one or more windings (7, 8), wherein the bulging portion (4) has a shape formed complementary and arranged opposite at a distance to a portion of the winding barrier system (11), wherein an additional barrier (13) is disposed between the winding barrier system (11) and the bulging portion (4), having a round portion (14) facing the bulging portion (4) and bent radially outward, and two flat planar portions (15, 16) each extending at an axial fold (17, 18) from the round portion (14) to a free end, characterized in that at least one actuator (22) is provided that extends between the winding barrier system (11) and the planar portion (15, 16) of the additional barrier (13).

2. The electrical device (9) according to claim 1, characterized in that the round portion (14) has a shape formed complementary to the bulging portion (4).

3. The electrical device (9) according to claim 1 or 2, characterized in that the planar portions (15, 16) each extend parallel to the planar wall portion of the side wall.

4. The electrical device (9) according to any one of the preceding claims, characterized in that the additional barrier (13) is held by means of at least one cap segment (19) disposed at a distance from the winding barrier system (11) and by means of a holding strap (21) at a distance from the winding barrier system (11) and the bulging portion (4).

5. The electrical device (9) according to claim 4, characterized in that each actuator (22) is fastened to the winding bar system (11) by means of the holding strap (21).

6. The electrical device (9) according to any one of the preceding claims, characterized in that each actuator (22) is fastened to the respective planar portion (16, 16) by means of a fastening cord (25).

7. The electrical device (9) according to any one of the preceding claims, characterized in that the winding barrier system (11) has a circular cylindrical outer contour and the bulging portion (4) delimits a portion of a circular hollow cylinder, wherein the winding barrier system (11) and the bulging portion (4) are disposed concentrically to one another.

8. The electrical device (9) according to any one of the preceding claims, characterized in that the bulging portion (4) and the round portion (14) each delimit a portion of a hollow cylinder, wherein the hollow cylinders have different radii, and the bulging portion (4) and the round portion (14) are disposed concentrically to one another.

9. The electrical device (9) according to claim 8, characterized in that, viewed from the top, the two edges (5, 6) of the side wall (2) and the two folds (17, 18) of the additional barrier (13) form the same angle with respect to the common centre.

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