EP2410553A1 - Gas-isolated high voltage switch - Google Patents

Abstract

The contact (40) has a rim guided around a central axis (A). A contact finger comprises a contact part (60) at a free lying end. A coil (43) comprises multiple windings of electrical conducting band such that slots (46) are formed. The slots are guided to free ends over one of front sides (45) of the coil in axial direction. The slots limit a stack of lamellas (47), which lie one over another. The lamellas are integrated in one of contact fingers (42). The lamellas support the contact part at an end that is turned away from a contact base (41). An independent claim is also included for a method for manufacturing a nominal current contact.

Description

TECHNICAL AREA

The present invention relates to a gas-insulated high voltage switch according to the preamble of claim 1.

A switch of the aforementioned type is generally designed as a circuit breaker and has a rated current carrying capacity of at least a few kA in the voltage range of more than a few kV. In general, this switch is used as a generator switch and therefore contains a high rated current loadable contact arrangement.

STATE OF THE ART

A high voltage switch of the aforementioned type is described in the brochure Generator Circuit Breakers Type HGl, Brochure No. 1 HC0015509E11 / AA06, ABB Switzerland AG, 8050 Zurich / Switzerland. The switch described includes a guided around a central axis ring of axially aligned and supported by an annular contact bottom contact fingers. The contact fingers have at an exposed end in each case a contact part, which rests with a closed switch with a predetermined, achieved by elastic deformation of contact springs or contact fingers contact force on a cylindrical mating contact of the rated current path of the switch electrically conductive. It is essential that the contact force applied by elastic deformation remains constant during operation of the switch.

PRESENTATION OF THE INVENTION

The invention, as indicated in the claims, the object is to provide a rated current contact of the type mentioned, its rated current carrying capacity can be increased without increasing its diameter, and at the same time provide a method that allows the production of such a rated current contact in a simple and cost-effective manner.

According to the present invention, there is provided a contact for the rated current path of a high voltage switch, comprising a collar guided by a central axis of axially aligned and supported by an annular contact bottom contact fingers, each having a contact portion at an exposed end, with the switch closed with a contact point rests on a cylindrical mating contact of the rated current path electrically conductive. At the contact bottom, a first two end faces of a hollow cylindrical winding is fixed, which contains a plurality of turns of an electrically conductive tape, are formed in the winding radially aligned and axially guided on the second end face of the winding slots, each of which two a stack of superimposed slats limit, which are integrated into one of the contact fingers, and carries the slat stack at its remote from the contact bottom free end of the contact part.

Because of the multi-part, lamellar structure of the contact fingers of the rated current contact can lead to a higher rated current according to the invention, without its diameter and, accordingly, the number of its contact fingers must be increased. Since the winding is easy to manufacture and easy to work, the current carrying capacity of the contact fingers determined by the thickness of the winding can be increased and thus the height of the rated current can be increased. Because of the greater material thickness of the contact fingers, the contact resistance of the rated current contact is reduced, so that when carrying an increased rated current, the permissible operating temperature is not exceeded. Accordingly, an unwanted relaxation of the contact fingers in continuous operation is avoided.

Such advantageous effects can not be achieved with a rated current contact according to the prior art, in which the contact finger ring is produced in an advantageous manufacturing technology by punching and bending a resilient copper sheet, as in this Contact the flexural rigidity of the contact fingers with the same bending length increases with the square of the thickness of the material and therefore the nominal current contact practically in its ideal fit, that is made almost without tolerances must be.

High-voltage switches equipped with a rated current contact according to the invention are preferably used as generator switches.

The turns of the winding can be welded to one another and to the contact part in the region of the first end side with one another and with the contact bottom and the lamellae at the free end of the lamination stack.

If the contacting point is arranged on a side of the contact part facing the axis, at least one groove for receiving a tension spring which can be guided about the axis can be formed in the side of the contact part facing away from the contacting point. It is achieved as an additional spring force of the contact fingers.

Additional spring force is also achieved if, in one embodiment of the rated current contact according to the invention, in which the contacting point is arranged on a side of the contact part facing away from the axis, at least one groove for receiving a compression spring which can be guided about the axis is formed in the side of the contact part facing away from the contacting point is.

If the material of at least one of the windings of the winding has a higher permissible bending stress than the material of the electrically conductive strip, then the spring force of the contact fingers and thus also the contact force of the rated current contact according to the invention increases. The at least one turn may be the inner or the outer turn of the winding. A particularly high contact force is achieved if at least two such windings are provided, which may be deposited successively, one of which may be the inner winding and the other the outer winding of the winding.

According to the present invention, there is also provided a method of making a contact for the rated current path of a high voltage switch, the rated current contact comprising a ring of about a central axis axially aligned and carried by a contact bottom contact fingers, each having a contact portion at an exposed end, which rests electrically conductive with a closed contact with a contact point on a cylindrical mating contact of the rated current path. In this method, the contact bottom and a contact ring are set at a distance from each other and to form an annular, radially outwardly open groove on a rotatable support of a mounting device, wherein the groove is bounded in each case by a molded into the contact bottom and a molded into the contact ring paragraph, is deposited forming a first and a second joint in the annular groove, a winding having a plurality of turns of an electrically conductive, corresponding to the width of the groove band, the first joint of the formed in an end face of the contact bottom heel and first ends of the turns and the second joint is bounded by the shoulder formed in the face of the contact ring and the second ends of the turns, in the first joint the first ends of the turns with each other and with the contact bottom and in the second joint the second ends of the turns with each other and with the contact ring firmly connected, and become after Removing the rotatable support formed in a raw body thus produced radially aligned slots which are guided parallel to the axis of the winding on the second joint and the contact ring to a remote from the contact bottom free end of the green body.

The contact bottom and the contact ring are particularly firmly connected to the winding when the first and second ends of the windings are welded together and with the contact bottom and the contact ring. In this case, electron beam welding has proved to be outstanding because of the high energy density of the electron beam.

In a quick and gentle way, the slots can be cut with a centrally oriented, axially guided water jet in the green body. In order to avoid abrasion due to re-radiation at silvered points of the green body, the water jet can be guided inclined relative to a plane aligned perpendicular to the axis. The spring resp. the contact force of the contact fingers can be increased in a simple manufacturing technology, if before or after depositing the electrically conductive tape at least one Winding the winding is stored, the material has a higher allowable bending stress than the material of the electrically conductive strip.

Further preferred embodiments and advantageous effects will be apparent from the following description and the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig.1

eine Aufsicht auf einen längs einer Achse A geführten Schnitt durch einen Hochspannungsschalter, der im links der Achse gelegenen Teil der Figur beim Ausschalten und im rechts der Achse gelegenen Teil im Einschaltzustand dargestellt ist und der zwei Nennstromkontakte nach der Erfindung aufweist,

Fig.2

eine in Richtung von Pfeilen geführte Aufsicht auf eine erste Ausführungsform eines der beiden Nennstromkontakte nach Fig.1,

Fig.3

eine in Pfeilrichtung geführte Aufsicht auf einen längs III-III geführten Schnitt durch den Nennstromkontakt gemäss Fig.2,

Fig.4

eine Aufsicht auf einen längs der Achse A geführten Schnitt durch einen bei der Fertigung des Nennstromkontakts gemäss den Figuren 2 und 3 entstehenden Rohkörper, der auf einer drehbaren Halterung einer bei der Fertigung verwendeten Montagevorrichtung festgesetzt ist,

Fig.5

eine Aufsicht auf einen längs der Achse A geführten Schnitt durch den auf einer Halterung einer Schneidevorrichtung festgesetzten Rohkörper gemäss Fig.4 während des Schneidens von Schlitzen,

Fig.6

die obere Hälfte eines bei der Fertigung einer zweiten Ausführungsform des Nennstromkontakts nach den Figuren 2 und 3 entstehenden Rohkörpers vorm Festsetzen in der Schneidevorrichtung nach Fig.5, und

Fig.7

die obere Hälfte eines bei der Fertigung des anderen der beiden Nennstromkontakte nach Fig.1 entstehenden Rohkörpers vorm Festsetzen in der Schneidevorrichtung nach Fig.5.

With reference to drawings, the invention will be explained in more detail below. Hereby shows:

Fig.1

a plan view of a guided along an axis A section through a high voltage switch, which is shown in the left of the axis located part of the figure when turned off and in the right part of the axis part in the on state and having two rated current contacts according to the invention,

Fig.2

a guided in the direction of arrows supervision of a first embodiment of the two rated current contacts after Fig.1 .

Figure 3

a guided in the direction of arrow supervision on a longitudinal III-III guided section through the rated current contact according to Fig.2 .

Figure 4

a plan view of a guided along the axis A section through a in the manufacture of the rated current contact according to the FIGS. 2 and 3 resulting raw body, which is fixed on a rotatable support of a mounting device used in manufacturing,

Figure 5

a plan view of a guided along the axis A section through the fixed on a holder of a cutting device raw body according to Figure 4 while cutting slits,

Figure 6

the upper half of a in the manufacture of a second embodiment of the rated current contact after the FIGS. 2 and 3 resulting raw body before setting in the cutting device according to Figure 5 , and

Figure 7

the upper half of one in the manufacture of the other of the two rated current contacts after Fig.1 resulting raw body before setting in the cutting device according to Figure 5 ,

WAYS FOR CARRYING OUT THE INVENTION

In all figures, like reference numerals designate like-acting parts. The in Fig.1 shown high voltage switch is designed as a generator switch and is typically designed for a rated voltage of 24 kV, a rated current of up to 8 kA, a permissible short-circuit current of 63 kA and a nominal frequency of 50/60 hertz. This switch has a housing which is filled with an arc-containing insulating gas, such as based on sulfur hexafluoride and / or nitrogen and / or carbon dioxide, of generally up to a few bar pressure. The illustrated in the figure upper part 10 of the housing includes a hollow cylindrical insulator 11 and two each serving as a power connection metal plates 12, 13, between which the insulator is flattened gas-tight. In the housing part 10 a to the power terminals 12, 13 is electrically connected contact arrangement is provided, which has two along an axis A relative to each other movable switching pieces 20 and 30. The contact piece 20 is connected to a drive, not shown, and - as indicated by a double arrow D - when closing along the axis A upwards and when opening along the axis A down.

The contact piece 20 has an arcing contact 21 in an axially symmetrical arrangement and a tubular contact current contact 22 surrounding it, whereas the contact piece 30 contains an arcing contact 31 in an axially symmetrical arrangement and two nominal current contacts 40 and 50 surrounding the arcing contact 31 at a distance and concentric with one another. The outer rated current contacts 40 include a ring of contact fingers, each with a contact point on the outer surface of the tubular rated current contact 22 rest, whereas the inner rated current contact 50 a ring of contact fingers each having a contact point on the inner surface of the rated current contact 22.

When the switch is closed, the rated current contact 22 is retracted into an annular space located between the two rated current contacts 40, 50, and the contact fingers of the two rated current contacts 40 and 50 are resiliently supported on the outer or inner surface of the tubular contact 22. One of the number of contact fingers corresponding high number of contact points favors the transmission of high rated currents. The arcing contact 31 is slidably mounted relative to the two rated current contacts 40, 50 along the axis A and is at the switch closed (right half of the figure) with its arc-free end formed by means of a prestressed spring 32 to form a sufficient contact force on the also arc-resistant supported free end of the arcing contact 21, so that the arcing contact 31 and the arcing contact 21 abut each other at the respective free end head to head.

When the switch is closed, the current is conducted mainly from the terminal 12 via a hollow cylinder 23, a sliding contact, not shown, the rated current contacts 22, 40, 50 and a designed as a hollow cylinder contact carrier 33 to the terminal 13. When switching off the drive D leads the contact piece 20 down. The in the switch-on position (right half of the figure) supported on the arcing contact 21 arc contact 31 is tracked by the prestressed spring 32 while maintaining the required contact force. First, the rated current contacts 22 and 40, 50 separate. The current commutes in a current path, which is formed by a cylinder bottom 24, the arc contacts 21, 31, a sliding contact, not shown, and the contact carrier 33. After a predetermined switching stroke of the contact piece 20 this proposes to a wall portion 34 of the contact carrier 33 (left half of Fig.1 ). When striking the two arc contacts separate 21, 31 and forms between the opposing free ends of the contacts 21, 31, a switching arc S, which burns in a radially outwardly bounded by an insulating nozzle 25 arc chamber. The arc generates hot, pressurized gas, which on the one hand via a heating channel 26 in a heating volume 27 and on the other via the insulating nozzle into the interior of the housing 10 expands. When approaching a zero crossing of the current to be disconnected, the gas stored in the heating volume 27, supported by compressed insulating gas from a compression space 28 of a piston-cylinder compression device actuated by the contact piece 20, blows the arc S, which leads to an interruption of the current.

The in the FIGS. 2 and 3 shown rated current contact 40 has clearly attachable to the contact carrier 33, annular, flat contact bottom 41, on the outer edge of the ring of the contact finger indicated by the reference numeral 42 is mounted. The contact fingers 42 are part of a Figure 3 apparent winding 43 of an electrically conductive tape, which is typically formed as a copper foil with a film thickness of up to one millimeter. This winding is attached to a first 44 of its two end faces 44, 45 on the outer edge of the contact bottom 41. In the winding 43 are radially aligned slots 46 ( Fig.2 ) formed, each of which is parallel to the axis A and from the front side menthaltenden level, eg from Fig.2 apparent level E, and which are extended to the second end face 45 of the winding 43. Each two adjacent slots define a stack 47 of superimposed, respectively from the layers. the turns of the winding 43 cut slats. At its free end located at the front end 45, the lamella stack 47 carries a contact part 60, which has a contacting point 61 resting on the outer surface of the rated current contact 22 when the switch is closed. With the aid of an electron beam, the turns of the winding 43 are welded to one another and to the contact base 41 in the region of the end face 44, whereas the lamellae are welded to one another at the free end of the lamination stack 47 and to the contact part 60 with the aid of the electron beam.

Because of the multi-part, layered structure of the contact fingers 42 of the guided by the contact 40 rated current can be increased without the diameter of the contact, respectively. the number of contact fingers has to be increased. By increasing the thickness of the winding 43 determined by the number of turns from, for example, 4 mm to 6 mm, the height of the rated current can be increased by approximately 20%, for example from 6.3 kA to 8 kA, without the prescribed operating temperature of typically 105 ° C is exceeded, and without the resilient contact fingers 42 in continuous operation relaxation.

In a rated current contact according to the prior art, in which the contact finger ring is produced in an advantageous manufacturing technology by punching and bending a resilient copper sheet, this is generally not possible. With such a rated current contact, the bending stiffness of the contact fingers increases with the same bending length with the square of the thickness of the material. This rated current contact must therefore be practically in its ideal fit, i. H. almost without tolerances

By a suitable choice of the electrically conductive band, for example, a band of hard copper instead of a soft copper, the flexural rigidity and thus the contact force of the contact fingers 42 can be increased. A further increase in the contact force is achieved by at least one annular, guided about the axis A tension spring 48. This spring is received by a circumferentially extending around the axis of the groove 62, which is formed at a side remote from the contact point 61 side in the contact part 60.

The rated current contact 40 is made as follows. On one off Figure 4 apparent, around the axis of symmetry A of the rated current contact 40 rotatable support 70 of a mounting device, the contact bottom 41 and the contact parts 60 containing contact ring 60 'with distance from each other and to form an annular, radially outwardly open groove attached. First, the contact ring 60 'formed substantially as a pipe section is fixed to a stop 71 of the holder 70. Thereafter, a tubular spacer 72 is pushed onto the holder 70 and supported on a side facing away from the stop 71 front side of the contact ring 60 '. In the outside of the spacer 72 lying portion of this end face is an annular about the axis A resp. the axis of the holder 70 guided paragraph 63 'formed, whereas in the inwardly facing side of the contact ring 60' containing the contact points, annular edge 61 'is formed. The contact bottom 41 is at an end face of the holder 70 by means of Fixed screws 74 and sets using the spacer 72, the contact ring 60 'firmly. In the outside of the spacer 72 lying outer edge of the contact base 41 is an annular about the axis A resp. the axis of the holder 70 guided paragraph 49 formed.

The paragraphs 49 and 63 'and the lateral surface of the spacer 72 define a radially outwardly open annular groove, in the formation of two joints 64' and 65 ', the winding 43 is stored. The joint 64 'is formed by the shoulder 49 and ends of the windings of the winding 43 supported on this shoulder and the joint 65' by the shoulder 63 'and windings of the winding 43 supported on this shoulder. The support forces are applied by a prestressed pipe strap 73, which is guided around the winding 43 and thus fixes the turns of the winding.

In the joint 64 'are supported on the shoulder 49 ends of the turns of the winding 43 with each other and with the contact bottom 41 and in the joint 65' welded on the shoulder 65 'turns of the winding 43 welded together and with the contact ring 60'.

After opening the pipe bracket 73 and loosening the screws 74, a thus manufactured blank 80 is removed from the holder 70 and on a likewise rotatable about the axis A, from Figure 5 apparent bracket 90 a cutting device fixed. In this cutting device, the slots 46 are cut into the green body 80. In a material-friendly manner, the slots 46 are made with a radially inwardly directed onto the axis A water jet WS, which is moved along the axis A. Since, in the manufacture of the slots 46, the water jet is also guided through the contact ring 60 ', and since the contact ring 60', in particular in the region of the edge 61 ', generally has a coating which increases the rated current carrying capacity of silver, care should be taken to ensure that Cutting due to reversion abrasion at the silver-coated areas of the green body, in particular the contact ring 60 ', is avoided. This is achieved in that the water jet WS is inclined relative to a plane E aligned perpendicular to the axis A by an angle α which is at least 20 to 30 °.

Another embodiment of the rated current contact 40 may be formed by molding the slots 46 in Figure 6 apparent raw body 80 are manufactured. In contrast to the raw body after Figure 4 is after the raw body Figure 6 an inner turn 43a of the winding 43 made of stainless spring steel strip with a thickness of typically 0.3 mm. This winding is applied to the shoulders 49, 63 'prior to winding the remaining turns of the soft or hard copper electrically conductive tape. The winding 43a significantly increases the flexural rigidity of the contact fingers 42. Thus, electrodynamic forces acting on the contact fingers 42 are reliably controlled. The at least one tension spring 48 can then be omitted in general.

In contrast to the raw body after Figure 6 becomes after the raw body Figure 7 used in the manufacture of the rated current contact 50, which applies the bending stiffness of the contact fingers 42 increasing turn only after winding the copper strip as the outer turn 43 b. This outer turn 43b substantially increases the bending stiffness of the contact fingers 42, especially when the edge 61 'resp. if the contact points 61 arising during cutting of the slots 46 are at a side of the contact ring 60 'facing away from the axis A, respectively. the contact parts 61 formed during cutting are arranged. In the axis A facing side of the contact ring 61 'resp. each of the contact parts 61 may one of the groove 62 'respectively. 62 corresponding groove formed, which serves to receive a guided about the axis A, the contact force of the contact fingers 42 increasing compression spring.

When the electrically conductive band is made of soft copper, a high current carrying capacity rated current contact can be achieved with spring stiffness of the contact fingers sufficient for certain applications, if the coil 43a or 43b is made of hard copper or other electrically conductive spring metal, or if at least two turns 43a or 43b or when both windings 43a or 43b containing respectively the aforementioned material are used.

LIST OF REFERENCE NUMBERS

10

casing

11

insulator

12, 13

power connectors

20

switching piece

21

Arcing contact

22

Current Rating Contact

23

hollow cylinder

24

connecting wall

25

insulating

26

heating duct

27

heating volume

28

compression chamber

30

switching piece

31

Arcing contact

32

contact spring

33

contact support

34

wall section

40

Current Rating Contact

41

Contact floor

42

contact fingers

43

winding

43a

inner winding of the winding 43

43b

outer winding of the winding 43

44.45

front sides

46

slots

47

laminate stack

48

mainspring

49

paragraph

50

Current Rating Contact

60

contact part

60 '

contact ring

61

contacting point

61 '

edge

62

groove

62 '

groove

63 '

paragraph

64 ', 65'

Put

70

rotatable holder of a mounting device

71

attack

72

spacer

73

pipe Bride

74

screw

80

green body

90

rotatable holder of a cutting device

A

axis

D

drive

e

level

S

Switching arc

WS

waterjet

Claims (11)

Contact (40, 50) for the rated current path of a high-voltage switch having a collar guided axially about a central axis (A) and having contact fingers (42) supported by an annular contact base (41) and each having a contact portion (60) at an exposed end. characterized in that when the switch is closed with a contact point (61) on a cylindrical mating contact (22) of the nominal current path electrically conductive, characterized in that at the contact bottom (41) has a first (44) of two end faces (44, 45) of a hollow cylindrical winding ( 43) is fastened, which contains a plurality of turns of an electrically conductive strip, that in the winding (43) radially aligned and on the second end face (45) of the winding (43) guided slots (46) are formed, of which two each a stack (47) of superimposed lamellae, which are integrated in one of the contact fingers (42), and that the lamella stack (47) at its from the K ontaktboden (41) facing away from the free end of the contact part (60). Rated current contact according to claim 1, characterized in that the turns of the winding (43) in the region of the first end face (44) with each other and with the contact bottom (41) and the lamellae at the free end of the lamella stack (47) with each other and with the contact part (60 ) are welded. Rated current contact according to one of claims 1 or 2, wherein the contact point (61) on one of the axis (A) facing side of the contact part (60) is arranged, characterized in that in the from the contact point (61) facing away from the contact part (60 ) at least one groove (62) for receiving a about the axis (A) feasible tension spring (48) is formed. Rated current contact according to one of Claims 1 or 2, in which the contacting point (61) is arranged on a side of the contact part (60) facing away from the axis (A), characterized in that the side of the contact part () facing away from the contacting point (61) 60) at least a groove for receiving a about the axis (A) feasible compression spring is formed. Rated current contact according to one of claims 1 to 4, characterized in that the winding (43) additionally contains at least one turn (43a, 43b) of a material, a higher allowable bending stress than the material of the electrically conductive tape. Rated current contact according to claim 5, characterized in that the at least one additional turn (43a, 43b) as inner (43a) or as an outer turn (43b) of the winding (43) is stored. Method for producing a contact (40, 50) for the rated current path of a high-voltage switch having a collar guided axially about a central axis (A) and having contact fingers (42) supported by a contact base (41), each of which has a contact part at an exposed end (60) which, when the switch is closed, with a contact point (61) on a cylindrical mating contact (22) of the rated current path electrically conductive, characterized in that the contact bottom (41) and a contact ring (60 ') with distance from each other and under education an annular, radially outwardly open groove on a rotatable support (70) of a mounting device are fixed, wherein the groove in each case by a in the contact bottom (41) and in the contact ring (60 ') molded-in shoulder (49; 63') limited in that, forming a first (64 ') and a second joint (65') in the annular groove, a winding (43) is laid which has several turns an electrically conductive strip corresponding to the width of the groove, the first joint (64 ') being formed by the shoulder (49) and first ends of the turns formed in an end face of the contact bottom (41) and the second joint (65') of the is limited in the end face of the contact ring (60 ') molded-in shoulder (63') and second ends of the turns that in the first joint (64 ') the first ends of the turns with each other and with the contact bottom (41) and in the second joint (65 ') the second ends of the turns are fixedly connected to each other and to the contact ring (60'), and that after removal of the holder (70) into a blank (80) produced in this way radially aligned slots (46) are formed, which parallel to the axis (A) of the winding (43) via the second joint (65 ') and the contact ring (60') to a contact bottom (41) facing away from the free end of the green body (80) are guided. A method according to claim 7, characterized in that the first and second ends of the turns are welded together and with the contact bottom (41) and the contact ring (60 '). A method according to claim 8, characterized in that the slots (46) with a centrally aligned, along the axis (A) guided water jet (WS) are cut into the green body (80). A method according to claim 9, characterized in that the water jet (WS) with respect to a plane perpendicular to the axis (A) aligned plane (E) is guided inclined. Method according to one of claims 7 to 10, characterized in that before or after depositing the electrically conductive strip at least one turn (43a, 43b) of the winding (43) is deposited, the material has a higher allowable bending stress than the material of the electrically conductive band.

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