WO2014180990A1

WO2014180990A1 - High ac connection arrangement with transposed conductors rails

Info

Publication number: WO2014180990A1
Application number: PCT/EP2014/059580
Authority: WO
Inventors: Aiman KERIM; Diego JOSSEN; Raeto STADLER; Rolf Schifferli
Original assignee: Abb Technology Ag
Priority date: 2013-05-10
Filing date: 2014-05-09
Publication date: 2014-11-13

Abstract

The invention relates to a high alternating current sharing arrangement, comprising a first electrical high current apparatus (1), a second electrical high current apparatus (3) and a high current connector (2), whereby the high current connector (2) electrically connects the apparatuses (1, 3) and is designed for transmitting high currents of ≥ 1000 Ampere between the apparatuses (1, 3), and the high current sharing connector (2) is divided into at least four parallel connected conductor rails (7) that run alongside one another between the apparatuses (1, 3), that are insulated with respect to one another and that are carried in an alternately interchanged position (10, 11) with respect to one another between the apparatuses (1, 3).

Description

HIGH AC CONNECTION ARRANGEMENT WITH TRANSPOSED CONDUCTORS RAILS

Technical Field

[0001] The invention relates to a high alternating current sharing arrangement, comprising a first electrical high current apparatus, a second electrical high current apparatus and a high current connector, whereby the high current connector electrically connects the apparatuses and is designed for transmitting high currents of≥ 1000 A between the apparatuses.

Background Art

[0002] High current applications for transmitting alternating currents of≥ 1000 A, for example between transformers and rectifiers, are often provided as massive, parallel bus bars, made out of aluminium and/or copper.

However, when transmitting electrical energy between apparatuses the electrical resistivity of the current connector should be as low as possible in order to reduce loss of energy and minimize heating. While for transmitting direct currents only the ohmic resistance is of interest, transmitting alternating currents, especially of alternating currents comprising > 1000 A, possess some challenges.

[0003] Of particular interest is the so called skin effect, which is the tendency of an alternating current of having a larger current density near the surface of the bus bar, as the current flows mainly at the "skin" of the bus bar between the outer surface and a level called the skin depth. The skin effect increases the resistance of the bus bar at higher frequencies where the skin depth is smaller, thus reducing the effective cross-section of the bus bar transmitting the current. In turn, as large bus bars have to be used for transmitting alternating currents of≥ 1000 A, the interior of such large bur bars carries little of the current, making the transmission very ineffective.

[0004] It is therefore an object of the invention to provide a current sharing

arrangement for effectively transmitting high currents of≥ 1000 A between a first electrical high current apparatus and a second electrical high current apparatus, in particular between a transformer and a rectifier. More particular, it is an object of the invention to provide an arrangement for transmitting currents of≥ 10.000 A between apparatuses while minimizing the material required for the respective current connector.

Summary of invention

[0005] The object is achieved by the features of the independent claim. Preferred embodiments are detailed in the dependent claims.

[0006] In particular, the object is solved by a high alternating current sharing

arrangement, comprising a first electrical high current apparatus, a second electrical high current apparatus and a high current connector, whereby the high current connector electrically connects the apparatuses and is designed for transmitting high currents of≥ 1000 A between the

apparatuses, and the high current sharing connector is divided into at least four parallel connected conductor rails that run alongside one another between the apparatuses, that are insulated with respect to one another and that are carried in an alternately interchanged position with respect to one another between the apparatuses.

[0007] Thus, the invention provides for a much better utilization of the current sharing connector^'s material compared to prior art systems, where many bus bars are directly connected straight in parallel, and thus for a much cheaper solution that is more compact in size. In particular, the solution proposed by the invention solves the prior art current sharing problem in AC connectors for high power i.e. high current applications, where parallel connection of multiple conductor rails is necessary in order to limit the current density value and thus the maximum operating temperature.

[0008] More particular, the current sharing connector, which is preferably

designed for transmitting currents of≥ 10 kA and more preferably of≥ 100 kA, is divided into at least four parallel connected conductor rails, which run alongside each other between the first electrical high current apparatus and the second electrical high current apparatus. All conductor rails are insulated with respect to each other preferably along their extension between the first electrical high current apparatus and the second electrical high current apparatus, while preferably not touching each other. Furthermore, all conductor rails are arranged between the first electrical high current apparatus and the second electrical high current apparatus such that all conductor rails alternately interchange positions with respect to one another. Preferably, the conductor rails alternately interchange positions with respect to one another between the

apparatuses in a symmetric, interlaced, twisted and/or interleaved manner in two-dimensional or three-dimensional plans. More preferably, each conductor rail is arranged between the first electrical high current apparatus and the second electrical high current apparatus such that the position of the average cross sectional area of all conductor rails along their extension is the same or comprises an offset that is smaller than the difference between the average cross sectional area of linear conductor rails. As a further advantage, the solution can be adapted easily for any current level by changing the number of the conductors. Thus, the arrangement is a very universal solution for high current application.

[0009] In sum, the solution according to the invention provides an improved

current sharing between the conductor rails and thus minimizes the neighbouring current influences as well. In particular, the solution according to the invention reduces the alternating current energy losses known from prior art connectors used for transmitting alternating currents of≥ 1000 A, as the high current connector is divided into multiple parallel connected connectors. Thus, the negative effect of having a larger current density near the surface a prior art single bus bar current connector, the so called skin effect reducing the effective cross-section of such prior art single bus bar current connectors, is significantly reduced by the solution according to the invention. This also means that alternating current energy losses are significantly reduced as well.

[0010] In other words, the solution according to the invention improves the high current sharing between apparatuses as higher operating current densities are reached within the current connector compared to prior art systems. As a direct result, less conductive material is required for the current connector, while the current can be transmitted at same operating temperatures as with prior art systems. As a further advantage, the solution according to the invention provides for a much cheaper solution as less material, for example aluminium or copper, is required for transmitting the currents, while in turn the solution is much more compact in size and thus allows for a much easier handling from mechanical and logistic point of view, as it allows multiple different design according to the required needs. Lastly, the solution according to the invention is also much more flexible in design from an electrical point of view. The term "high current" should be understood as capable of generating, transmitting, sharing, transforming and/or consuming currents of ≥ 1000 A, preferably of > 10 kA and more preferably of > 100 kA.

[001 1] According to another preferred embodiment the conductor rails are carried in alternately interchanged positions with respect to one another in both vertical and horizontal positions in regard to the respective end of each conductor rail. For example, a first conductor rail connected with one end to the first electrical high current apparatus on position "left, above" is connected with the other end to the second electrical high current apparatus on position "right, below". A second conductor rail connected with one end to the first electrical high current apparatus on position "left, below" is connected with the other end to the second electrical high current apparatus on position "right, above". In case of eight conductor rails, for example, a conductor rail connected to the first electrical high current apparatus on position "left, second most above" is connected to the second electrical high current apparatus on position "right, second most below". Such positioning allows for very efficiently reducing the negative effects of the skin effect and results in much less alternating current energy losses compared to prior art systems.

[0012] According to another preferred embodiment, the first electrical high current apparatus comprises a first terminal, the second electrical high current apparatus comprises a second terminal, each terminal having a first side and a second, opposed side, and half of the conductor rails are connected each by a connection means to the first side of the first terminal and to the second side of the second terminal, and the other half of the connectors are connected each by a connection means to the second side of the first terminal and to the first side of the second terminal. In other words, it is preferred that the conductor rails are attached to the terminals such that the conductor rails cover the terminals from both sides at each terminal, while the conductor rails change the sides between the terminals when running alongside one another between the apparatuses. Preferably, the terminal comprises a metal sheet, preferably comprising aluminium and/or copper, and a rectangular dimension of, for example, 20 cm x 50 cm. More preferably, the terminals are attached to the high current apparatuses in a vertical manner above ground such that the surfaces, for example of the metal sheets, of the terminals are essentially planar to each other, whereby the longitudinal sides of the terminals face each other. More preferably, the conductor rails run alongside one another between the apparatuses in a direction essentially planar to the surfaces of the metal sheets of the conductor rails. The connection means might be provided as a bore within the terminal and/or as a screw with nut for fixing each two conductor rails preferably at their ends with the terminal through the bore such that most preferably the two conductor rails with their ends cover the terminal from both first and opposed second sides.

In this regard it is especially preferred that each terminal comprises a first connection position and a second, offset connection position, and half of the conductor rails are connected each by the connection means to the first position of the first terminal and to the second position of the second terminal, and the other half of the connectors are connected each by the connection means to the second position of the first terminal and to the first position of the second terminal. Thus, not only the sides are exchanged as per above detailed embodiment, but also the positions, e.g. from "second most above" on one terminal to "second most below" on the other terminal, allowing for a very efficient reduction of the skin effect due a symmetric change of the sides and positions between the terminals. [0014] According to another preferred embodiment each two different conductor rails connected to the first side and to the laterally reversed second side of a respective terminal are both connected by four connection means.

Preferably, the connection is carried out by screws with nuts thus providing a very stable connection between the terminal and the conductor rail.

Furthermore, instead of four there might also be two, eight or even more connection means provided, for example depending on the weight of the terminals to be connected.

[0015] According to another especially preferred embodiment, the conductor rail comprises along its extension an offset. Preferably and exemplary, the offset is provided such that the conductor rail changes, when connected to terminals on both ends, its position from "most above, first side" on the first terminal to "second most above, second side" on the second terminal. More preferably, the offset is provided as a bend, kink and/or cranking between two linear extensions of the conductor rail and is provided along the extension of the conductor rail at a position of 2/3, 3/4 or 4/5 of the extension of the conductor rail. Most preferably, all conductor rails are each provided with the same dimensions and offsets at each the same positions in order to avoid circulating currents between the conductor rails. Thus, it is preferred that all conductor rails change, along their extensions, their position and side between the terminals in the same circular manner such that in turn each conductor rails works basically under the same magnetic proportion.

[0016] According to an especially preferred embodiment the conductor rails run contact-free with respect to one another between the apparatuses along their extension and/or are insulated by an insulation means between the apparatuses. Thus, the insulation can be simply provided by air or any other sufficient insulation means, for example by a plastic shielding the conductor rail along its extension. Such insulating means has to be removed at the area of the conductor rail that is connected to the terminal in order to allow for the electrical connection between the terminal and the conductor rail. [0017] According to another preferred embodiment the high alternating current sharing arrangement comprises an insulating horizontal prop arranged at an interchanged position between two conductor rails. Such horizontal prop may comprise an insulating material such as a ceramic, plastic or any other similar insulating means, or a metal comprising an electrically insulating shielding. Preferably a horizontal prop is arranged at each interchanging position of each two conductor rails, thus supporting and/or adjusting the structure of the conductor rails along their extension between the apparatuses and improving the insulation between the conductor rails.

[0018] In this regard it is especially preferred according to another embodiment that the high alternating current sharing arrangement comprises a vertical prop arranged for supporting the horizontal prop and/or the conductor rails. The vertical prop can be provided as a metal stand and might be insulated, for example, by an insulating shielding. Preferably, the vertical prop is provided and/or arranged on ground between the two apparatuses and mechanically connected to all vertical props and/or to the conductors rails in an insulated manner. Thus, the vertical prop allows for supporting, in combination with the horizontal props, the conductor rails i.e. the weight of the conductor rails, for example, against bending and deflexion and thus avoids any short circuits between the conductor rails along their

extensions between the apparatuses.

[0019] According to another preferred embodiment the conductor rail comprises a stretch means, the stretch means extends away from an alongside running parallel conductor rail and the stretch means preferably comprises multiple layers of metal sheets arranged closed to one another and having a width and/or height as the conductor rail. Preferably, the metal sheets comprise the same material as the conductor rails, for example Aluminium. Such stretch means might be provided as a "sharp bend" and is preferably arranged close to an end of the conductor rail. The stretch allows for adjusting temperature variations causing the conductor rails to stretch and/or lengthen, while the conductor rails are preferably fixed to the apparatuses. [0020] According to another preferred embodiment the high alternating current sharing arrangement comprises 4, 6, 8, 10, 12, 14 and/or 16 conductor rails. Preferably, each electrical high current apparatus comprises two, three, four or five terminals arranged in row. Such embodiments allow for transmitting of very high currents of, for example, more than 100 kA between the electrical high current apparatuses in a very efficient manner by significantly reducing the skin effect and the related alternating current energy losses.

[0021] According to another preferred embodiment the conductor rail is bar- shaped, comprises a length of > 50 cm and < 250 cm, preferably of > 100 cm and≤ 200 cm and most preferably of 150 cm, a width of≥ 50 mm and < 150 mm, preferably of≥ 75 mm and≤ 175 mm and most preferably of 100 mm and/or a height of≥ 10 mm and≤ 30 mm, preferably of≥ 15 mm and≤ 25 mm and most preferably of 20 mm. Preferably, each conductor rail comprises the same length, width and height. According to another embodiment the conductor rail comprises aluminium and/or copper and/or is provided as a bus bar, as a flexible bus bar, as a laminated bus bar or as a cable. Alternatively, the conductor rails can be solid, flexible, laminated or stranded, for example provided as multiple laminated aluminium profiles. Such conductor rails provide for the transmission of alternating currents of more than 100 kA and alternating voltages of more than 1500 V between the apparatuses, while in turn significantly reducing alternating current energy losses.

[0022] According to another preferred embodiment the first high current

apparatus comprises a rectifier, a frequency rectifier and/or a power unit, and/or the second high current apparatus comprises a transformer and/or a current source. Such rectifiers and/or transformers are, for example, commercially available from ABB and operate under high alternating currents. In addition, the apparatus might be provided as any other high current apparatus known from prior art, thereby allowing the invention to provide for an efficient high current transmission in a very flexible and universal way for a wide range of current applications. Thus, the invention significantly improves the high current sharing between such apparatuses, as higher current densities are reached within the connector made up by the paralleled conductor rails compared to prior art systems, while operating under same operating temperatures as said prior art systems.

[0023] According to another preferred embodiment, the high alternating current sharing arrangement comprises a cooling means adapted for cooling the high current connector by air and/or liquid and/or comprising open areas between the conductor rails running alongside one another between the apparatuses. Such cooling further improves the transmission of the currents between the apparatuses.

Brief description of drawings

[0024] These and other objects of the invention will become apparent in

connection with the following description in conjunction with the

accompanying drawing:

[0025] Fig. 1 shows a high alternating current sharing arrangement according to a preferred embodiment of the invention in a schematic view.

Description of embodiments

[0026] Fig. 1 shows a high alternating current sharing arrangement according to a preferred embodiment of the invention in a schematic view. The high alternating current sharing arrangement comprises a schematically shown first electrical high current apparatus 1 , which is a transformer providing a current of > 10 kA and < 100 kA and a voltage of > 500 V and < 1500 V. The first electrical high current apparatus 1 is connected via a high current connector 2 to a schematically shown second electrical high current apparatus 3, which is provided as a rectifier.

[0027] The first electrical high current apparatus 1 comprises two first terminals 4 and the second electrical high current apparatus 3 comprises two second terminals 5, whereby each terminal 4, 5 is provided as a vertical extending bus bar comprising massive aluminium. Each terminal 4, 5 comprise twenty-four holes 6, arranged between a first side 8 of the terminal 4, 5 and the second, opposed side 9 of the terminal 4, 5. [0028] The terminals 4, 5 are electrically connected by twenty-four conductor rails 7, whereby each twelve conductor rails 7 are connected to one terminal 4, 5 by screws 6 through the holes 6. Between the terminals 4, 5 the conductor rails 7 run alongside one another and are carried in an alternately interchanged position with respect to one another. In particular, each conductor rail 7 end' is connected to one terminal 4, 5 by connection means 6 of four screws 6 running through the holes 6 such that two different conductor rails 7 cover at least a part of one terminal 4, 5 from the first side 8 of the respective terminal 4, 5 and the laterally reversed second side 9 of the respective terminal 4, 5.

[0029] Furthermore, each four conductor rails 7 alternately interchange their position between the two terminals 4, 5 with respect to one another conductor rail 7 in both vertical and horizontal position. As can be seen from Fig. 1 , the highest conductor rail 7 of the first terminal 4 is connected to the first terminal 4 in a first position 10 on the first side 8 of the terminal 4. The respective conductor rail 7 runs from the first terminal 4 towards the second terminal 5 and is connected to the second terminal 5 in a second, offset position 1 1 , which is arranged below the first position 10, on the second side 9 of the second terminal 5. In turn, the conductor rail 7 connected to the second position 1 1 on the first side 8 of the second terminal 5, runs from the second terminal 5 to the first terminal 4 being connected to the first terminal 4 on the first position 10 and on the second side 9.

[0030] Each conductor rail 7 comprises along its extension an offset 12 for

changing the side 8, 9 and position 10, 1 1 on the way from the first terminal 4 to the second terminal 5. Such way, the high current sharing connector 2 is divided into said twenty-four conductor rails 7 running alongside one another between the terminals 4, 5 respectively between the apparatuses 1 , 3.

[0031] Furthermore, all conductor rails 7 are insulated with respect to each other by running contact-free between the opposed terminals 4, 5. In other words, the twenty-four conductor rails 7 are mechanically and electrically not in touch along their extensions, are interlaced respectively twisted and/or interleaved in 2D or 3D dimension plans along their extension between the opposed terminals 4, 5, whereby open air areas are provided between the conductor rails 7 for insuring air flow as respective insulation and cooling. Alternatively, an insulating means 13, such as plastic or an insulating shielding, might be provided for insulating the conductor rails 7 along their extensions.

[0032] Each high current connector 2 is designed for transmitting currents of≥ 1000 A between the apparatuses 1 , 3. Therefore, each conductor rail 7 comprises bar-shaped massive aluminium rods having a height of 20 mm and width of 100 mm, while extending between the opposed terminals 4, 5 by 150 cm. For compensating temperature variations, the conductor rails 7 each comprise a stretch means 14, which extends away from an alongside, parallel running conductor rail 7. The stretch means 14 comprises multiple layers of aluminium sheets arranged close to one another and having the same width and height as the conductor rail 7.

[0033] Horizontal props 15 are provided at interchanged position between each two conductor rails 7 for ensuring that the respective two conductor rails 7 are insulated from each other. Therefore, the horizontal props 15 are provided as plastic or ceramic elements arranged between two conductor rails 7 and touching both the two conductor rails 7. For mechanically supporting the horizontal prop 15, and therefore also for mechanically supporting the conductor rails 7 respectively the weight of the conductor rails 7 along their extension between the terminals 4, 5, a metallic vertical prop 16 is provided that is connected with the horizontal prop 15, which is arranged on ground between the apparatuses 1 , 3. The arrangement furthermore comprises a cooling means 17 adapted for cooling the high current connector 2 by air and/or liquid.

[0034] While the invention has been illustrated and described in detail in the

drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

[0035] Other variations to be disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting scope.

Reference signs list

1 first electrical high current apparatus

2 high current connector

3 second electrical high current apparatus

4 first terminal

5 second terminal

6 hole, screws, connection means

8 first side

9 second side

10 first position

1 1 second position

12 offset

13 insulating means

14 stretch means

15 horizontal prop

16 vertical prop

17 cooling means

Claims

Claim 1. High alternating current sharing arrangement, comprising a first

electrical high current apparatus (1 ), a second electrical high current apparatus (3) and a high current connector (2), whereby

the high current connector (2) electrically connects the apparatuses (1 , 3) and is designed for transmitting high currents of≥ 1000 Ampere between the apparatuses (1 , 3), and

the high current sharing connector (2) is divided into at least four parallel connected conductor rails (7) that run alongside one another between the apparatuses (1 , 3), that are insulated with respect to one another and that are carried in an alternately interchanged position (10, 1 1) with respect to one another between the apparatuses (1 , 3).

Claim 2. High alternating current sharing arrangement according to the

preceding claim, whereby the conductor rails (7) are carried in alternately interchanged positions with respect to one another in both vertical and horizontal positions (8, 9, 10, 1 1 ) in regard to the respective end of each conductor rail (7).

Claim 3. High alternating current sharing arrangement according to one of the preceding claims, whereby the first electrical high current apparatus (1 ) comprises a first terminal (4), the second electrical high current apparatus (3) comprises a second terminal (5), each terminal (4, 5) having a first side (8) and a second, opposed side (9), and half of the conductor rails (7) are connected each by a connection means (6) to the first side (8) of the first terminal (4) and to the second side (9) of the second terminal (5), and the other half of the connectors (7) are connected each by a connection means (6) to the second side (9) of the first terminal (4) and to the first side (8) of the second terminal (5).

Claim 4. High alternating current sharing arrangement according to the

preceding claim, whereby each terminal (4, 5) comprises a first connection (10) position and a second, offset connection position (1 1 ), and half of the conductor rails (7) are connected each by the connection means (6) to the first position (10) of the first terminal (4) and to the second position (1 1 ) of the second terminal (5), and the other half of the connectors (7) are connected each by the connection means (6) to the second position (1 1 ) of the first terminal (4) and to the first position (10) of the second terminal (5).

Claim 5. High alternating current sharing arrangement according to the

preceding claim, whereby each two different conductor rails (7) connected to the first side (8) and to a laterally reversed second side (9) of a respective terminal (4, 5) are both connected by four connection means (6).

Claim 6. High alternating current sharing arrangement according to one of the preceding claims, whereby the conductor rail (7) comprises along its extension an offset (12).

Claim 7. High alternating current sharing arrangement according to one of the preceding claims, whereby the conductor rails (7) run contact-free with respect to one another between the apparatuses (1 , 3) and/or are insulated by an insulation means (13) between the apparatuses (1 , 3).

Claim 8. High alternating current sharing arrangement according to one of the preceding claims, comprising an insulating horizontal prop (15) arranged at an interchanged position between two conductor rails (7).

Claim 9. High alternating current sharing arrangement according to the

preceding claim, comprising a vertical prop (16) arranged for supporting the horizontal prop (15) and/or the conductors rails (7).

Claim 10. High alternating current sharing arrangement according to one of the preceding claims, whereby the conductor rail (7) comprises a stretch means (14), the stretch means (14) extends away from an alongside, parallel running conductor rail (7) and the stretch means (14) preferably comprises multiple layers of metal sheets arranged close to one another and having a width and/or height as the conductor rail (7).

Claim 1 1. High alternating current sharing arrangement according to one of the preceding claims, comprising 4, 8, 12, and/or 16 conductor rails (7).

Claim 12. High alternating current sharing arrangement according to one of the preceding claims, whereby the conductor rail (7) is bar-shaped, comprises a length of≥ 50 cm and≤ 250 cm, preferably of≥ 100 cm and≤ 200 cm and most preferably of 150 cm, a width of≥ 50 mm and≤ 150 mm, preferably of≥ 75 mm and≤ 175 mm and most preferably of 100 mm and/or a height of≥ 10 mm and≤ 30 mm, preferably of≥ 15 mm and≤ 25 mm and most preferably of 20 mm.

Claim 13. High alternating current sharing arrangement according to one of the preceding claims, whereby the conductor rail (7) comprises aluminium and/or copper and/or is provided as a bus bar, a flexible bus bar, a laminated bus bar or as a cable.

Claim 14. High alternating current sharing arrangement according to one of the preceding claims, whereby the first high current apparatus (1) comprises a transformer and/or a current source, and/or the second high current apparatus (2) comprises a rectifier, a frequency rectifier and/or a power unit.

Claim 15. High alternating current sharing arrangement according to one of the preceding claims, comprising a cooling means (17) adapted for cooling the high current connector (2) by air and/or liquid and/or comprising open areas between the conductor rails (7) running alongside one another between the apparatuses (1 , 3).