High voltage disconnector

Abstract

A high voltage disconnection unit includes a fixed contact assembly having at least a first fixed main contact and a first fixed auxiliary contact, a movable contact assembly having at least a first movable main contact and a first movable auxiliary contact that rotate with respect to the first fixed main contact and first fixed auxiliary contact from a contacts closed position to a contacts open position. During an opening operation of the disconnection unit the separation of the first movable main contact from the first fixed main contact takes place before the separation of the first movable auxiliary contact from the first fixed auxiliary contact. The relative opening speed V1 between the first movable auxiliary contact and the first fixed auxiliary contact is greater than the relative opening speed V2 between the first movable main contact and the first fixed main contact.

Claims

1. A high voltage disconnection unit comprising: a fixed contact assembly having at least a first fixed main contact and a first fixed auxiliary contact, and a movable contact assembly having at least a first movable main contact and a first movable auxiliary contact that rotate with respect to the first fixed main contact and the first fixed auxiliary contact from a closed position to an open position, wherein the first movable main contact comprises a plurality of contact strips operatively couplable to the fixed contact assembly for providing a current path when the high voltage disconnection unit is in the closed position; wherein during an opening operation of the high voltage disconnection unit, separation of the first movable main contact from the first fixed main contact takes place before separation of the first movable auxiliary contact from the first fixed auxiliary contact; and wherein a relative auxiliary opening speed between the first movable auxiliary contact and the first fixed auxiliary contact is greater than a relative main opening speed between the first movable main contact and the first fixed main contact.

2. The high voltage disconnection unit, according to claim 1, wherein said movable contact assembly comprises an elastic device acting on said first movable auxiliary contact with a snapping action that imparts to said first movable auxiliary contact said relative main opening speed.

3. The high voltage disconnection unit, according to claim 2, wherein said elastic device comprises a spring device.

4. The high voltage disconnection unit, according to claim 1, wherein said first movable main contact rotates around a first rotation axis and said first movable auxiliary contact rotates around a second rotation axis, said relative auxiliary opening speed being a rotation angular speed of said first movable auxiliary contact around said second rotation axis, said relative main opening speed being a rotation angular speed of said first movable main contact around said first rotation axis.

5. The high voltage disconnection unit, according to claim 4, wherein said second rotation axis is pivotally fixed on said first movable main contact, a relative position of said second rotation axis with respect to said first fixed main and auxiliary contacts changing during a rotation of said first movable main contact.

6. The high voltage disconnection unit, according to claim 1, wherein said first movable main contact comprises first and second contact arms parallel to and spaced apart from each other along a first rotation axis, said first movable auxiliary contact being positioned in between said first and second contact arms.

7. The high voltage disconnection unit, according to claim 1, wherein said fixed contact assembly comprises a fixed contact body, said first fixed main contact comprising first and second contact surfaces positioned on opposite faces of said fixed contact body, said first fixed auxiliary contact comprising a third contact surface positioned on a bottom portion of said fixed contact body, said first and second contact surfaces being substantially parallel to each other, said third contact surface being substantially perpendicular to said first and second contact surfaces.

8. The high voltage disconnection unit, according to claim 7, wherein said first movable main contact comprises first and second contact arms parallel to and spaced apart from each other along a first rotation axis, said first movable auxiliary contact being positioned in between said first and second contact arms; and wherein said first and second contact arms of said first movable main contact comprise the contact strips on their respective facing surfaces, said contact strips being operatively couplable to said first and second contact surfaces of said fixed contact body, said first movable auxiliary contact comprising a contact support rigidly fixed on said second rotation axis and a contact head at an end of said contact support, said contact head being operatively couplable to said third contact surfaces of said fixed contact body.

9. The high voltage disconnection unit, according to claim 8, wherein said movable contact assembly comprises an elastic device acting on said first movable auxiliary contact with a snapping action that imparts to said first movable auxiliary contact said relative main opening speed, and wherein said elastic device comprises first and second torsion springs coaxially mounted on said second rotation axis between said contact support and said first and second contact arms, respectively.

10. The high voltage disconnection unit, according to claim 1, wherein in the closed position of said disconnection unit said first movable main contact is coupled to said first fixed main contact, while said first movable auxiliary contact is uncoupled from said first fixed auxiliary contact, and wherein the opening operation of said disconnection unit comprises a first step in which the first movable main contact rotates and remains in contact with the first fixed main contact while the first movable auxiliary contact is brought into contact with the first fixed auxiliary contact, a second step in which the first movable main contact continues to rotate and is uncoupled from said first fixed main contact with said relative main opening speed while the first movable auxiliary contact is bent back in a direction opposite to a rotation direction of said first movable main contact and slides on said first fixed auxiliary contact maintaining an electrical contact, a third step in which the first movable main contact continues to rotate while the first movable auxiliary contact snaps away from said first fixed auxiliary contact with said relative auxiliary opening speed, and a fourth step in which both said first movable main and auxiliary contacts are uncoupled from a corresponding first fixed main and auxiliary contacts.

11. The high voltage disconnection unit, according to claim 10, wherein said movable contact assembly comprises an elastic device acting on said first movable auxiliary contact with a snapping action that imparts to said first movable auxiliary contact said relative main opening speed, and wherein in said third step said first movable auxiliary contact snaps away from said first fixed auxiliary contact by rotation in a direction the same as the rotation direction of said first movable main contact under an action of said elastic device.

12. The high voltage disconnection unit, according to claim 1, further comprising at least a second fixed contact assembly which is spaced apart form said first fixed contact assembly.

13. The high voltage disconnection unit, according to claim 12, further comprising a third fixed contact assembly which is spaced apart form said first and second fixed contact assemblies, one of said second and third fixed contact assembly being at ground potential.

14. A high voltage switchgear comprising the disconnection unit according to claim 1.

15. A high voltage disconnection unit comprising: a fixed contact assembly; a movable contact assembly; the fixed contact assembly comprising a first fixed main contact and a first fixed auxiliary contact; the movable contact assembly comprising a first movable main contact and a first movable auxiliary contact; and the first movable main contact and the first movable auxiliary contact being respectively rotatable with respect to the first fixed main contact and the first fixed auxiliary contact in between a closed position and an open position, wherein the first movable main contact comprises a plurality of contact strips operatively couplable to the fixed contact assembly for providing a current path when the high voltage disconnection unit is in the closed position.

16. The high voltage disconnection unit, according to claim 15, further comprising: during an opening operation of the high voltage disconnection unit, separation of the first movable main contact from the first fixed main contact taking place before separation of the first movable auxiliary contact from the first fixed auxiliary contact.

17. The high voltage disconnection unit, according to claim 15, further comprising: a relative auxiliary opening speed between the first movable auxiliary contact and the first fixed auxiliary contact being greater than a relative main opening speed between the first movable main contact and the first fixed main contact.

18. The high voltage disconnection unit, according to claim 15, further comprising: the high voltage disconnection unit being operated in between the closed position and the open position; in response to the high voltage disconnection unit being in the closed position, the first movable main contact being coupled to the first fixed main contact while the first movable auxiliary contact being uncoupled from the first fixed auxiliary contact; an opening operation of the high voltage disconnection unit from the closed position to the open position comprising: a first step in which the first movable main contact rotates and remains in contact with the first fixed main contact while the first movable auxiliary contact rotates and is brought into contact with the first fixed auxiliary contact; a second step in which the first movable main contact continues to rotate and is uncoupled from the first fixed main contact while the first movable auxiliary contact continues to rotate and is bent back in a direction opposite to a rotation direction of the first movable main contact and slides on the first fixed auxiliary contact so as to maintain an electrical contact; a third step in which the first movable main contact remains in non-contact with the first fixed main contact while the first movable auxiliary contact continues to rotate and snaps away from the first fixed auxiliary contact; and a fourth step in which the first movable main contact remains in non-contact with the first fixed main contact while the first movable auxiliary contact continues to rotate and is uncoupled from the first fixed auxiliary contact.

19. The high voltage disconnection unit, according to claim 18, further comprising: the second step in which the first movable main contact continues to rotate and is uncoupled from the first fixed main contact with a relative main opening speed; the third step in which the first movable auxiliary contact continues to rotate and snaps away from the first fixed auxiliary contact with a relative auxiliary opening speed; and the relative auxiliary opening speed being greater than the relative main opening speed.

Description

(1) Further features and advantages of the present invention will be more clear from the description of preferred but not exclusive embodiments of a high voltage disconnection unit of the present invention, shown by way of examples in the accompanying drawings, wherein:

(2) FIG. 1 is a perspective view of an embodiment of a high voltage disconnection unit, according to the invention, in the contact closed position;

(3) FIG. 2 is a perspective view of an embodiment of a high voltage disconnection unit, according to the invention, in the contact open position;

(4) FIG. 3 is a more detailed perspective view of an embodiment of a high voltage disconnection unit, according to the invention, in the contact open position;

(5) FIG. 4 is a second perspective view of an embodiment of a high voltage disconnection unit, according to the invention, in the contact closed position;

(6) FIG. 5 is a perspective view of a first phase of the opening operation of a high voltage disconnection unit, according to the invention;

(7) FIG. 6 is a perspective view of a second phase of the opening operation of a high voltage disconnection unit, according to the invention;

(8) FIG. 7 is a perspective view of a third phase of the opening operation of a high voltage disconnection unit, according to the invention;

(9) FIG. 8 is a second perspective view of an embodiment of a high voltage disconnection unit, according to the invention, in the contact open position.

(10) With reference to the attached figures, the high voltage disconnection unit of the present invention, designated by the reference numeral 1, in its more general definition, comprises a fixed contact assembly 2, which has at least a first fixed main contact 21 and a first fixed auxiliary contact 22.

(11) The disconnection unit 1 further comprises a movable contact assembly 3, which has at least a first movable main contact 31 and a first movable auxiliary contact 32 that rotate with respect to said first fixed main contact 21 and first fixed auxiliary contact 22 from a contacts closed position to a contacts open position. According to known embodiments, the first movable main contact 31 can be operatively connected to a motor drive, e.g. a rotating motor electronically controlled, that imparts to said first movable main contact 31 a rotation movement to carry out the desired opening or closing operation.

(12) One of the distinguishing features of the disconnection unit 1 of the present invention is given by the fact that during an opening operation of said disconnection unit 1 the separation of said first movable main contact 31 from said first fixed main contact 21 takes place before the separation of said first movable auxiliary contact 32 from the corresponding first fixed auxiliary contact 22.

(13) Furthermore, the disconnection unit 1 of the present invention is characterized in that the relative opening speed V1 between the first movable auxiliary contact 32 and said first fixed auxiliary contact 22 is greater than the relative opening speed V2 between said first movable main contact 31 and said first fixed main contact 21.

(14) In other words, in the disconnection unit 1 of the present invention the separation between the main contacts 21 and 31 takes place at different times and with different speeds with respect to the separation between the auxiliary contacts 32 and 22.

(15) In a typical embodiment of a high voltage disconnection unit 1, the movable contact assembly 3 further comprises an elastic device 4 acting on said first movable auxiliary contact 32 with a snapping action that imparts to said first movable auxiliary contact 32 said opening speed V2. In other words, while the first movable main contact 31 is moved at a speed V2 by, e.g., a motor drive, the opening operation of the first movable auxiliary contact 32 is actuated by the elastic device 4 with a snapping action at a speed V1 which is greater than the speed V2 of the first movable main contact 31

(16) Preferably, said elastic device 4 can conveniently comprise a spring device, for example one or more torsion springs suitably positioned.

(17) In the embodiments shown, the opening/closing operation of the high voltage disconnection unit 1 takes place by rotation of said first movable main contact 31 around a first rotation axis 310 and by rotation of said first movable auxiliary contact 32 around a second rotation axis 320.

(18) With particular reference to FIGS. 1-3, the position of the first rotation axis 310 is fixed with respect to said to said first fixed main 21 and auxiliary 22 contacts, while the second rotation axis 320 is pivotally fixed on said first movable main contact 31, in particular in an eccentric position of it with respect to said first rotation axis 310.

(19) In practice, the opening speed V1 is given by the rotation angular speed of the first movable auxiliary contact 32 around said second rotation axis 320, while the opening speed V2 is given by the rotation angular speed of the first movable main contact 31 around said first rotation axis 310.

(20) Thus, the relative position of said second rotation axis 320 with respect to said first fixed main 21 and auxiliary 22 contacts changes during a rotation of said first movable main contact 31. In particular, in the closed position of FIG. 1, the second rotation axis 320 is positioned between the first rotation axis 310 and the fixed main 21 and auxiliary 22 contacts, while in the open position of FIGS. 2 and 3 the second rotation axis 320 is moved counterclockwise and its distance from the fixed main 21 and auxiliary 22 contacts is increased.

(21) In the embodiments of a high voltage disconnection unit 1 shown in the attached figures, said first movable main contact 31 comprises a first 311 and a second 312 contact arms which are parallel to each other. Also, the first 311 and second 312 contact arms are spaced apart from each other along said first rotation axis 310, thereby leaving a space between them.

(22) In this way, said first movable auxiliary contact 32 can be conveniently positioned in said space between said first 311 and second 312 contact arms, thereby obtaining a very compact structure of the movable contacts assembly 3.

(23) As shown in the embodiments of attached figure, the fixed contact assembly 2 comprises a fixed contact body 20 having an elongated shape that protrudes toward the movable contact assembly 3.

(24) The first fixed main contact 21 then comprises a first 211 and a second 212 contact surfaces which are positioned on opposite faces of said elongated fixed contact body 20, while said first fixed auxiliary contact 22 comprises a third contact surface 223 which is positioned on a bottom portion of said fixed contact body 20, i.e. at the end of fixed contact body 20 close to the movable contact assembly 3.

(25) In practice, as clearly shown in the attached figure, the first 211 and second 212 contact surfaces are substantially parallel to each other, while the third contact surface 223 is substantially perpendicular to said first 211 and second 212 contact surfaces.

(26) Thus, from a construction standpoint, the fixed contact assembly 2 can be conveniently formed by a single fixed contact body 20, having two parallel surfaces 211 and 212 on a first and a second opposite face forming said first and second contact surfaces. The fixed contact body 20 is also provided with a third surface 223, on a third face perpendicular to said first and second opposite faces of said fixed contact body 20, forming said third contact surface. In this way, the overall design of the fixed contact assembly 2 can have a very compact design and can be manufactured very easily.

(27) With particular reference to the embodiment shown in FIGS. 2 and 3, the first 311 and second 312 contact arms of said first movable main contact 31 each comprise contact strips 350 which are positioned on their respective facing surfaces, i.e. on the surfaces of the first 311 and second 312 contact arms facing each other.

(28) The contact strips 350 are operatively couplable to said first 211 and second 212 contact surfaces of said fixed contact body 20 and provide a nominal current path when the disconnection unit 1 is in the closed position.

(29) Then, the first movable auxiliary contact 32 comprises a contact support 321 which is in the form of an elongated body having a first end rigidly fixed on said second rotation axis 320 and a contact head 322 at a second end of said contact support 321.

(30) The contact head 322 is operatively couplable to said third contact surfaces 223 of said fixed contact body 20 and provide a commutated current path during a phase of the opening operation of the disconnection unit 1.

(31) In an embodiment of the high voltage disconnection unit 1, said elastic device 4 comprises a first 41 and second 42 torsion springs coaxially mounted on said second rotation axis 320 between said contact support 321 and said first 311 and second 312 contact arms, respectively.

(32) With reference to the attached FIGS. 4-8, the opening operation of the high voltage disconnection unit 1 of the invention can be described as follows.

(33) With reference to FIG. 4, in a closed position of said disconnection unit 1 the first movable main contact 31 is coupled to said first fixed main contact 21, thereby providing a nominal current path, while said first movable auxiliary contact 32 is uncoupled from said first fixed auxiliary contact 22.

(34) Then, with reference to FIG. 5, in a first step of the opening operation, the first movable main contact 31 rotates, e.g. counterclockwise, and remain into contact with the first fixed main contact 21 while the first movable auxiliary contact 32 is brought into contact with the first fixed auxiliary contact 22. During this phase the current may flow through both the main 21, 31 and auxiliary 22, 32 contacts system with an intensity that depends upon the contact resistance of the main 21, 31 and auxiliary 22, 32 contacts system.

(35) As previously said, in a more general embodiment of the high voltage disconnection unit 1, in the closed position both first movable main 31 and auxiliary 32 contacts are engaged with the corresponding fixed main 21 and auxiliary 22 contacts and in such a case the above described first step is not present.

(36) In a second step of the opening operation, shown in FIG. 6, the first movable main contact 31 continues to rotate counterclockwise and is uncoupled from the first fixed main contact 21 (main contacts opening) with said opening speed V2 while the first movable auxiliary contact 32 is bent back clockwise in a direction opposite to the rotation direction of said first movable main contact 31 and slides on said first fixed auxiliary contact 21 maintaining an electrical contact with it. During this phase the current path is therefore commutated from the main contacts system to the auxiliary contact systems. At the same time, the mechanical interference between the first movable auxiliary contact 32 and the first fixed auxiliary contact 22, which forces the first movable auxiliary contact 32 to be bent back and rotate clockwise, brings about loading of the elastic means 4.

(37) The first movable main contact 31 then continues to rotate counterclockwise and the first movable auxiliary contact 32 slides on the first fixed auxiliary contact 21 while its rotation axis 320 is moved away from the fixed contact assembly until when the position of FIG. 7 is reached.

(38) In such position, the forces exerted by the elastic means 4 overcome the mechanical resistance between the first movable auxiliary contact 32 and the first fixed auxiliary contact 22. The first movable auxiliary contact 32 is therefore free to quickly snap away from said first fixed auxiliary contact 22 by rotating counterclockwise with said opening speed V1 which is substantially given by the rotation angular speed of said first movable auxiliary contact 32 around its rotation axis 320.

(39) Finally, with reference to FIG. 8, in the open position both said first movable main 31 and auxiliary 32 contacts are uncoupled from the corresponding first fixed main 21 and auxiliary 22 contacts.

(40) The opening operation of the high voltage disconnection unit 1 has been described with reference to a counterclockwise motion of the first movable main contact 31 and an initial clockwise motion of the first movable auxiliary contact 32, followed by a counterclockwise snap action of the same. The operation can obviously takes place in a similar manner by rotating the first movable main contact 31 clockwise and the first movable auxiliary contact 32 initially counterclockwise and then clockwise.

(41) According to particular embodiments of the high voltage disconnection unit 1 not represented in the attached figures, said disconnection unit 1 can comprise at least a second fixed contact assembly.

(42) The second fixed contact assembly is conveniently spaced apart from the first fixed contact assembly 2 and lies in the rotation plane of the first movable main contact 31. In practice, according to this embodiment the first movable main contact 31 can be coupled with any of the first 2 or second fixed contact assembly by rotation through successive contact positions. Furthermore, said disconnection unit 1 can comprise a third fixed contact assembly which is spaced apart form said first 2 and second fixed contact assemblies and lies in the rotation plane of said first movable main contact 31, one of said second 2 and third fixed contact assembly being at ground potential. In this way it is possible to carry out the typical combined disconnection and earthing operation of a high voltage switchgear

(43) It is clear from the above description that the presently disclosed high voltage disconnection unit fully solve the underlined technical problems of the prior art disconnection units.

(44) In particular the high separation speed between the auxiliary fixed and main contacts that can be achieved with the present invention allows reducing the arc duration with respect to the conventional disconnection units. As a consequence, the ablation of the contact surfaces in case of formation of an electrical arc is significantly reduced. This has a very positive impact not only on the operative life of the disconnection unit but also on its capability to pass the Bus Transfer standard test with a certain safety margin as well as more in general to increase the power test performances.

(45) Moreover, since the ablation of the contact is significantly reduced due to less arc exposure, the risk of pre-striking during the closing operation is also significantly reduced, thereby greatly improving the performances of the high voltage disconnection unit also during the closing operation.

(46) It also worth noting that the structure of the disconnection unit is extremely simple and with a reduced number of components, thereby minimizing the manufacturing and maintenance costs. In addition the structure is extremely compact and allows to greatly optimize the spaces and the volumes within the disconnection unit.

(47) Several variations can be made to the high voltage disconnection unit thus conceived, all falling within the scope of the attached claims. In practice, the materials used and the contingent dimensions and shapes can be any, according to requirements and to the state of the art.