EP2845213B1 - Three-position load isolating switch for medium-voltage switchgear assemblies - Google Patents

Description

The invention relates to a three-position circuit breaker for medium-voltage switchgear with a main contact system, formed of a first fixed contact and a second fixed contact, which are diametrically opposed, and a rotatable by means of a centrally between the first fixed contact and the second fixed contact rotary support movable contact forming a main current path in a first position of the moving contact, forming a separation distance in a second position of the rotatable moving contact and forming a grounding position with a grounding contact system in a third position of the rotatable moving contact, and a Nebenstrompfad formed from the first fixed contact, the second fixed contact, a quenching contact system and a first Sliding contact and a second sliding contact for forming a conductive connection with the rotatable moving contact in one between the first position and the second position En turning angle range of the rotatable moving contact such that upon initiation of a rotary motion in the rotatable moving contact commutation of an alternating current flowing through the switching device from the main current path is made possible on the Nebenstrompfad, wherein the rotatable moving contact means for interrupting the extinguishing contact system, and with extinguished arc and initiate another Rotary movement is a forming the separation distance is possible, wherein the extinguishing contact system comprises a vacuum interrupter.

A switch disconnector for medium voltage switchgear is for example from DE 10 2004 006 476 A1 and comprises a main contact system and a shunt branch, in which shunt branch an erase contact arrangement for extinguishing an arc and a disconnect contact arrangement for providing a dielectric strength are provided.

A three-position circuit breaker of the type mentioned is from the EP 0693763 B1 known.

Object of the present invention is to form a three-position circuit breaker of the type mentioned, which is inexpensive to produce in a compact design.

This is achieved according to the invention in that the means comprise a cam for actuating a rocker coupled to a moving contact connecting bolt of the vacuum interrupter by means of a guide element and the means further comprise a folding mechanism such that when the three-position load disconnecting switch is switched on, the third or second position of the rotatable movement contact in its first position the extinguishing contact system is interrupted.

Such a three-position circuit breaker on the one hand has a compact design, because by the diametrical arrangement of the first fixed contact and second fixed contact to each other and the interposed rotatable moving contact an arrangement of main flow path and Nebenstrompfad in a small space next to each other is made possible by the rotational movement of a commutation of the Switching device guided alternating current from the main current path to the secondary current path is made possible. On the other hand, such a switching device has a cost-effective design, because by the arranged in the secondary current path extinguishing contact system both this and the first and second sliding contacts and other connecting means to the first and the second fixed contact of inexpensive material, such as steel or stainless steel or aluminum or the like , can be produced because a current is only briefly conducted during a switching operation via the secondary current path until, after arc quenching in the extinguishing contact system, a transfer to the disconnected position of the three-position circuit breaker takes place, so that the requirements on the material properties of the secondary flow path are lower than the requirements for the material properties of the main flow path. The structure with cam is mechanically simple and thus compact and inexpensive, since with this structure only work against the low spring force of the contact pressure spring of the extinguishing contact system is to perform and by the folding mechanism is ensured in an advantageous manner that a switch-on of the switching device by initiating the rotational movement in the opposite direction and transfer of the rotatable moving contact from the third or the second position to the first position of the switching is carried out without electrical interference over the Nebenstrompfad and in particular without involvement of the vacuum interrupter of the extinguishing contact system, so that the vacuum interrupter no requirements regarding Einschaltfestigkeit or the like be set because a Einschaltlichtbogen is ignited during the switching between the rotatable moving contact and the first and second fixed contacts, which in particular in the arrangement of the Dreistellungslastentrennschalter in a filled with an insulating medium, such as an insulating gas or insulating liquid housing represents a simple, in contrast to the switching in the vacuum interrupter cost-effective way to perform a switch-on.

In an advantageous embodiment of the invention, the vacuum interrupter on a closable by means of a contact pressure spring contact system. The contact system of the vacuum interrupter is held by the contact pressure spring in its closed state, as long as the means of the rotatable moving contact to interrupt the extinguishing contact system does not attack this, so that only a small spring force is necessary because of the arrangement of the extinguishing contact system in the secondary flow path, in particular for the contact pressure spring No short-circuit current is supplied, switched on or off via the secondary current path.

In an advantageous embodiment of the invention, the grounding contact system is formed by a ground contact, the second sliding contact as a ground counter contact and the rotatable movement contact. As a result, a three-position circuit breaker is formed with the positions ON, OFF and EARTH in a simple and compact manner.

Figur 1:

ein Ausführungsbeispiel eines erfindungsgemäßen Schaltgerätes in einer ersten Position;

Figuren 2 und 3:

das Schaltgerät der Figur 1 in einer Trennstellung bzw. einer Erdungsstellung;

Figur 4:

eine Ansicht eines Ausführungsbeispiels eines dreiphasigen Schaltgerätes gemäß dem Schaltgerät der Figur 1.

The invention will be explained in more detail below with reference to the drawing and an embodiment with reference to the accompanying figures. Show it:

FIG. 1:

an embodiment of a switching device according to the invention in a first position;

FIGS. 2 and 3:

the switching device of FIG. 1 in a disconnected position or a grounding position;

FIG. 4:

a view of an embodiment of a three-phase switching device according to the switching device of FIG. 1 ,

FIG. 1 shows a three-position circuit breaker 1 for use in medium-voltage switchgear, which are not shown in detail figuratively, the three-position circuit breaker 1 is connected to a first fixed contact 2 with a busbar connection of the switchgear and a second fixed contact 3 with a cable outlet of the medium voltage switchgear is connectable. The first fixed contact 2 and the second fixed contact 3, which are preferably formed of copper as a material, together with a rotatable moving contact 4 form a main contact system and a main current path of the three-position circuit breaker 1. The moving contact 4 is designed as a pair of knives and comprises a first pair of knife ends 5 and a second pair of knife ends 6 and a figuratively not shown further conductive connection between the first pair of knife ends 5 and second pair of knife 6 and is located in the FIG. 1 in a first Position in which the first pair of knife ends 5 forms a conductive connection with the first fixed contact 2 and the second pair of knife ends 6 with the second fixed contact 3 forms a conductive connection, so that a current flow through the three-position circuit breaker 1 and over the main current path is possible. The rotatable moving contact 4 is attached to a rotary support 7, in which rotary support 7, a drive movement of a figuratively also not shown drive for rotating the rotary support 7, and thus rotation of the rotatable moving contact 4 is possible. On the first fixed contact 2, an erase contact system 9 is electrically connected by means of a conductive connection 8, which extinguishing contact system 9 is formed by a vacuum interrupter 10 with moving contact 11 and fixed contact 12, wherein the extinguishing contact system 9 in the FIG. 1 is in the closed state by a contact pressure spring 13 on a moving contact terminal pin 14 exerts a compressive force to hold in the closed position of the extinguishing contact system 9. The moving contact 11 of the extinguishing contact system 9 is in turn conductively connected to a first sliding contact 15. A second sliding contact 16 by means of a further conductive connecting element 17 to the second fixed contact 3 electrically conductively connected, so that after initiating a rotary movement in the rotary support 7 and rotation of the rotatable moving contact 4 in a contact position in which the first knife pair end 5 and the second knife pair end 6 of the rotatable Moving contact 4 with the first sliding contact 15 and the second sliding contact 16 is in conductive connection, a Nebenstrompfad on the first fixed contact 2, the conductive connection 8, the closed erase contact system 9, the first sliding contact 15, the rotatable moving contact 4, the second Slip contact 16, the conductive connecting member 17 and the second fixed contact 3 is formed, as with respect to the FIG. 2 explained in more detail below. The first sliding contact 15 and the second sliding contact 16 may be formed of steel, for example. On the rotatable moving contact 4 is still provided a cam 18, which has a cam track 19 through which in a Rotary movement of the rotatable moving contact 4, a rocker 20 is actuated, which rocker 20 is rotatably mounted at a pivot point 21 and guided by a guide pin 22 in its movement along the curved path, wherein a guide member 23 is provided, through which the rocker 20, the moving contact terminal bolt 14 of the extinguishing contact system 9 moves and the extinguishing contact system 9 opens. The cam track 19 in this case has a first portion 19 ', whose course is provided for opening the extinguishing contact system 9, and a second portion 19 "with a maximum radius, is ensured by the holding open the extinguishing contact system via the guide pin 22.

A ground contact 24 of a ground contact system is provided for forming a ground position of the three-position circuit breaker 1, which will be described later. On the cam 18, a folding mechanism 25 is arranged, which has a rotary lever 26 and a spring lever 27 and a spring 28, and which is provided so that when a switch-on of the three-position circuit breaker 1, the erase contact system 9 remains in its open state, while the rotatable moving contact 4 is transferred from the grounding position or the switch-off position back into the first position by introducing an opposite rotational movement by virtue of the curved track 19 retaining its maximum radius by the folding mechanism, as explained in greater detail below. When switching off the spring lever 27, which is rotatably supported on the rotary lever 26, pivoted by the guide pin 22 forced out of its position FIG. 1 away, but as soon as the maximum radius has reached the same by the rotational movement of the guide pin 22 on the curved path, transferred by the spring 28 back to its original position, so that in a switch-on and a rotational movement back into the area of the curved path 19 the maximum radius and the erase contact system 9 is held by the guided on the maximum radius guide pin 22 in the open state. The three-position switch-disconnector 1 is included
arranged in a housing 29 which can be filled with an insulating gas or an insulating liquid and by means of fastening elements, of which only one example is denoted by 30, can be fastened and mounted on the medium-voltage switchgear.

The function of the three-position circuit breaker 1 of FIG. 1 will be described below on the basis of FIGS. 1 to 3 explained in more detail. As already stated above, the three-position switch-disconnector 1 is in the FIG. 1 In its first position with trained main current path via the first fixed contact 2, the rotatable moving contact 4 and the second fixed contact 3. When initiating a drive movement in the rotary support 7 to perform a switching operation and finally to form a separation path for dielectric separation is first a figuratively not shown Achieved position in which the first pair of knife ends 5 is in conductive connection with both the first fixed contact 2 and the first sliding contact 15 and the second pair of knife ends 6 is in electrically conductive connection with the second fixed contact 3 and the second sliding contact 16, so that at this time, a commutation of the main current path is introduced to the secondary current path with the extinguishing contact system 9 closed. Upon further rotational movement, the first knife pair end 5 and the second knife pair end 6 are then only in conductive connection with the first sliding contact 15 and the second sliding contact 16, so that the main current path is interrupted and the commutation is completed. In this case, the cam 18 engages with its curved path 19 on the rocker 20 so that is caused by rotation of the rocker 20 about the pivot point 21 via the guide member 23 of the moving contact terminal pin 14 of the extinguishing contact system 9 to a movement, which against the spring force of the contact pressure spring 13 can be introduced and leads to the opening of the extinguishing contact system 9, so that an arc in the extinguishing contact system 9 of the vacuum interrupter 10 is ignited in the secondary flow path, which at a current zero crossing of the guided via the switching device AC is deleted. Upon further rotation, the position of the FIG. 2 reached, in which the rotatable moving contact 4 is in a second position with trained disconnected position and completely interrupted current flow, further the cam 18 with its curved path 19 still attacks the rocker 20 and the extinguishing contact system 9 of the secondary flow path remains open, and between the Knife pair ends 5 and 6 and the fixed contacts 2 and 3 or sliding contacts 15 and 16 is a sufficient distance to meet a dielectric separation condition of the switching device or the medium-voltage switchgear.

In other words, between the first position of the switched state of the three-position circuit breaker 1 of the FIG. 1 and the second position with formed separation distance of the three-position load circuit breaker 1 of FIG. 2 by initiating a rotational movement in the rotary support 7 and thus the rotatable moving contact 4, a rotation angle range of the rotatable moving contact 4 so passed through that initially a commutation of the alternating current flowing through the switching device from the main current path is made possible on the secondary current path and at extinguished arc and further rotational movement training the Separation distance under reaching the second position of the FIG. 2 is possible.

When initiating further rotational movement of the rotatable moving contact 4 finally reaches its third position as in FIG. 3 shown, in which it is in conductive connection with the second fixed contact 3 on the one hand via the first knife pair end 5 and the ground contact 24 via the second knife pair end 6, so that a grounding of all the second fixed contact 3 is in a conductive connection system parts.

A switch-on of the three-position circuit breaker 1 is done by initiating a rotational movement in the opposite direction to the rotational movement of the switching of the in the disconnected position or the grounding position three-position circuit breaker 1, as in FIG. 3 represented, and rotation of the rotatable moving contact 4 back to the position of FIG. 1 until the first pair of knife ends 5 comes into conductive connection with the first fixed contact 2 and the second pair of knife ends 6 with the second fixed contact 3.

By the folding mechanism 25 is ensured that when switching the extinguishing contact system 9 remains in its open state, because by the spring 28 of the spring lever 27, the maximum radius of the cam track for guiding the guide pin 22 results, as already described above.

This makes it possible to cost-effectively carry out the vacuum interrupter 10 of the extinguishing contact system 9, since this is not involved in the switch-on and thus no special requirements for the switch-on of the vacuum interrupter 10 must be made. Furthermore, in the arrangement of the secondary flow path can be formed by low-cost materials such as steel, stainless steel or aluminum, because on the secondary flow path only briefly briefly a current is performed and in particular no short-circuit current occurs in the secondary flow path.

FIG. 4 shows a three-phase switching device 1, wherein each phase 31, 32 or 33 according to the embodiment of FIGS. 1 to 6 is formed, of which the housing 29 are visible and wherein the individual phases 31, 32 and 33 are interconnected via connecting elements 34, so that a simultaneous actuation of all phases by initiating a rotational movement of a drive not shown in the rotary support 7 is made possible. The grounding contacts 24 of the phases 31, 32 and 33 are connected to each other via a ground rail 35, which in turn is grounded. A frame 36 is as a holder of the three-position load break switch 1 and for arranging busbar terminals 37, 38 and 39th and provided by cable outlet terminals 40, 41 and 42 of the switchgear.

LIST OF REFERENCE NUMBERS

1

Three-position switch disconnectors

2

first fixed contact

3

second fixed contact

4

moving contact

5

first pair of knife ends

6

second pair of knife ends

7

rotary supporters

8th

conductive connection

9

Extinguishing contact system

10

Vacuum interrupter

11

moving contact

12

fixed contact

13

Contact pressure spring

14

Moving contact terminal bolts

15

first sliding contact

16

second sliding contact

17

connecting element

18

cam

19

cam track

19 '

first section

19 "

second part

20

seesaw

21

pivot point

22

guide pins

23

guide element

24

ground contact

25

Hinge

26

lever

27

spring lever

28

feather

29

casing

30

fastener

31, 32, 33

phases

34

fasteners

35

ground bus

36

frame

37, 38, 39

Busbar connections

40, 41, 42

Cable outlet ports

Claims (3)

1. Three-position load isolating switch (1) for medium-voltage switchgear assemblies having a main contact system, formed from a first fixed contact (2) and a second fixed contact (3), said fixed contacts being arranged diametrically opposing one another, and from a moving contact (4) which can be rotated by means of a rotary support (7) which is arranged centrally between the first fixed contact (2) and the second fixed contact (3), so as to form a main current path in a first position of the rotatable moving contact (4), so as to form an isolating distance in a second position of the rotatable moving contact (4) and so as to form an earthing position with an earthing contact system in a third position of the rotatable moving contact, and also from a secondary current path which is formed from the first fixed contact (2), from the second fixed contact (3), from an arc-quenching contact system (9) and also from a first sliding contact (15) and a second sliding contact (16) for forming a conductive connection to the rotatable moving contact (4) in a rotation angle region of the rotatable moving contact (4), said rotation angle region being located between the first position and the second position, such that when a rotary movement in the rotatable moving contact (4) is initiated, commutation of an alternating current which flows via the switching device from the main current path to the secondary current path is made possible, wherein the rotatable moving contact (4) has means (18, 19, 25) for interrupting the arc-quenching contact system (9), and when the arc is quenched and a further rotary movement is initiated, formation of the isolating distance is enabled, wherein the arc-quenching contact system (9) comprises a vacuum interrupter (10), wherein the means (18, 19, 25) comprise a cam disk (18) for actuating a rocker (20) coupled by means of a guide element (23) to a moving contact connecting pin (14) of the vacuum interrupter (10),
   c h a r a c t e r i s e d in that
   the means (18, 19, 25) further comprise a tilting mechanism (25) such that during a making operation of the three-position load isolating switch (1) from the third or second position of the rotatable moving contact (4) into its first position, the arc-quenching contact system (9) is interrupted.
2. Switching device according to claim 1,
   characterised in that
   the vacuum interrupter (10) has a contact system which is closable by means of a contact pressure spring (13).
3. Switching device according to claim 1 or 2,
   characterised in that
   the earthing contact system is formed by an earthing contact (24), the second fixed contact (3) as the earthing countercontact and the rotatable moving contact (4).

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