Patent Application
20120256711
This application claims priority under 35 U.S.C. §119 to European Application No. 11161924.3 filed in Europe on Apr. 11, 2011, the content of which is hereby incorporated by reference in its entirety.
The present disclosure relates to a switch, such as a high or medium voltage switch a first and a second set of contact elements that are mutually displaceable. The disclosure also relates to a current breaker comprising such a switch.
The present disclosure relates to a switch having a first and a second set of contact elements and a drive adapted to displace one of the contact elements along a displacement direction. Each contact element carries at least one conducting element. In a first mutual position of the contact elements, their conducting elements combine to form at least one conducting path between the first and second terminals of the switch, in a direction transversally to the displacement direction. In a second position of the contact elements, the conducting elements are mutually displaced into staggered positions and therefore the above conducting path is interrupted.
An exemplary high or medium voltage switch is disclosed comprising: a first and a second terminal; a first and a second set of contact elements arranged between the first and the second terminal; and a first drive connected to said first set of contact elements adapted to mutually displace the sets of contact elements along a displacement direction, wherein each contact element includes an insulating carrier carrying at least one conducting element, wherein in a first mutual position of said contact elements the at least one conducting element of each contact element forms at least one conducting path in an axial direction between said first and said second terminals in a direction transversally to said displacement direction, wherein in a second mutual position of said contact elements the at least one conducting element of each contact element is mutually displaced and do not form said conducting path, wherein the switch includes a second drive connected to said second set of contact elements, and wherein said first and second drives are adapted to simultaneously move said first and second set, respectively, in opposite directions.
An exemplary current breaker is disclosed comprising: a switch including a first and a second terminal, a first and a second set of contact elements arranged between the first and the second terminal; and a first drive connected to said first set of contact elements adapted to mutually displace the sets of contact elements along a displacement direction, wherein each contact element includes an insulating carrier carrying at least one conducting element, wherein in a first mutual position of said contact elements the at least one conducting element of each contact element forms at least one conducting path in an axial direction between said first and said second terminals in a direction transversally to said displacement direction, and wherein in a second mutual position of said contact elements the conducting elements are mutually displaced and do not form said conducting path, and wherein the switch includes a second drive connected to said second set of contact elements, wherein said first and second drives are adapted to simultaneously move said first and second set, respectively, in opposite directions said current breaker comprising: a primary electrical branch and a secondary electrical branch in parallel; at least one solid state breaker arranged in the primary electrical branch; and a plurality of solid state breakers arranged in series in the secondary electrical branch, wherein a number of solid state breakers in the secondary electrical branch is larger than a number of solid state breakers in the primary electrical branch, and wherein said switch is arranged in said primary electrical branch in series to said solid state breaker of said primary electrical branch.
The disclosure will be better understood and embodiments and advantages other than those set forth above will become apparent from the following detailed description thereof. Such description makes reference to the annexed drawings, wherein:
Exemplary embodiments of the present disclosure are directed to a switch having a first and a second terminal for applying the current to be switched. Further, the switch has a first and a second set of contact elements and a drive adapted to mutually displace the contact elements relative to each other along a displacement direction. Each contact element includes an insulating carrier that carries at least one conducting element. The positions of the conducting elements are such that:
(1) in a first mutual position of the contact elements the conducting elements form one or more conducting paths along an axial direction between the first and the second terminals, i.e. the switch is in the closed, conducting position; and
(2) in a second mutual position of the contact elements the conducting elements are mutually displaced such that the conducting path does not form, i.e. the switch is in its opened, non-conducting position.
The switch includes a first and a second drive, with each drive being connected to one of said sets of contact elements. The first and a second drives are adapted to simultaneously, i.e. concurrently or during the same time window, move the first and second set, respectively, in opposite directions. By this measure, the relative contact separation speed as well as the total contact separation distance are basically doubled, which allows faster switching and reduces the travel length of each drive resulting in a fast buildup of dielectric strength across the contact gap.
Each drive can include an electrical drive coil and a movable member, wherein the movable member can be moved between a first and a second location and is connected to the first or second set of contact elements, respectively. The first location corresponds to the first mutual position of the contact elements and the second location corresponds to the second mutual position of the contact elements, or vice versa. Each drive is adapted to accelerate the movable member from the first position to the second position, in a direction away from the drive coil, when a current flows through the drive coil. Thus, current pulses through the drive coils can be used to close or open the switch.
Hence, in yet a further advantageous embodiment, the switch includes a current pulse generator structured to generate concurrent current pulses in the drive coil of the first drive and the drive coil of the second drive, thereby achieving a concurrent actuation of both drives.
A very simple design to ensure a concurrent motion is achieved by arranging the drive coil of the first drive electrically in series to the drive coil of the second drive. Thus, any current pulse simultaneously acts on both drives.
The drives can be arranged within the housing, thus obviating the need for mechanical bushings.
The switch can be used in high voltage applications (i.e. for voltages above 72 kV, for example), but it can also be used for medium voltage applications (e.g., between some kV and 72 kV).
Other exemplary embodiments are listed in the dependent claims, combinations of dependent claims as well as in the description below together with the figures.
Housing 1 forms a GIS-type metallic enclosure of manifold type and includes two tube sections. A first tube section 3 extends along an axial direction A, and a second tube section 4 extends along a direction D, which is called the displacement direction for reasons that will become apparent below. Axial direction A can be perpendicular or nearly perpendicular to displacement direction D. The tube sections are formed by a substantially cross-shaped housing section 5.
Housing 1 can be at ground potential (e.g. in a GIS=gas-insulated substation), but it may also be on high voltage potential (e.g. in a life tank breaker).
First tube section 3 ends in first and second support insulators 6 and 7, respectively. First support insulator 6 carries a first terminal 8 and second support insulator 7 carries a second terminal 9 of the switch. The two terminals 8, 9 extending through the support insulators 6, 7 carry the current through the switch, substantially along axial direction A.
Second tube section 4 ends in a first and a second cap or flange portion 10 and 11, respectively.
First terminal 8 and second terminal 9 extend towards a center of space 2 and end at a distance from each other, with a switching arrangement 12 located between them, at the intersection region of first tube section 3 with second tube section 4.
The contact elements 13a, 13b, 13c, 14a, 14b, 14c can be moved along the displacement direction D into a second position, where the conducting elements 16 are staggered in respect to each other and do not form a conducting path. In
To achieve such a displacement, and as best can be seen in
In the exemplary embodiments shown in
The drives 18, 19 can e.g. operate on the repulsive Lorentz-force principle and be of the type shown in U.S. Pat. No. 7,235,751, which is herewith incorporated by reference in its entirety. Each drive is able to displace one set of contact elements along the displacement direction D. They are adapted and controlled to move the first and second sets in opposite directions at the same time in order to increase the travelling length and speed of displacement. An exemplary embodiment of a suitable drive is described in more detail below.
The drives 18, 19 are arranged in opposite end regions of second tube section 4.
The full stroke (e.g. 20 mm per drive) of the drives may not be necessary to travel in order for the contact system to provide the specified dielectric strength, but a distance much shorter (e.g. 10 mm per drive) may suffice, which can be reached in an even shorter time. This arrangement can also provides certain safety in case of back-travel upon reaching the end-of-stroke position and damping phase of the actuators.
As shown in
Conducting element 16 can include an aluminium body with silver coating.
In the exemplary embodiment of
In the exemplary embodiment of
When the circuit breaker is in its closed current-conducting state, all solid state breakers are conducting and switch 27 is closed current-conducting state. The current substantially bypasses secondary branch 29, because the voltage drop in primary branch 28 is much smaller. Hence, for nominal currents, the losses in the circuit breaker are comparatively small.
When the current is to be interrupted, in a first step the solid state breaker(s) 30 in primary branch 28 are opened, which causes the current in primary branch 28 to drop to a small residual value that is then interrupted by opening switch 27. Now, the whole current has been commuted to secondary branch 29. In a next step, the solid state breakers 31 in secondary branch 29 are opened.
Hence, in the opened state of the circuit breaker of
The switch described above is well suited for such an application as switch 27 because of its fast switching time and its large dielectric strength.
Bistable suspension 38 includes first and second pistons 39, 40 movable along bores 41, 42 in a direction perpendicular to displacement direction D. The pistons are pushed towards chamber 36 by means of first and second springs 43, 44. Each piston 39, 40 is connected to movable member 37 by means of a link 45, 46. Each link 45, 46 is formed by a substantially rigid rod, which is, at a first end, rotatably connected to its piston 39, 40, and, at a second end, rotatably connected to movable member 37.
The springs 43, 44 urge the links 45, 46 against movable member 37. Thus, movable member 37 can assume two stable locations within bistable suspension 38, namely a first location as shown with solid lines in
To operate movable member 37, first and second drive coils 47, 48 are arranged at opposite sides of chamber 36. Further, movable member 37 is of a conducting material, at least on its surfaces facing the drive coils 47, 48. In the first and second stable locations, movable member 37 is adjacent to first and second drive coil 47, 48, respectively.
Hence, when movable member 37 is e.g. in its first location and a current pulse is sent through first drive coil 47, a mirror current is generated within movable member 37, which leads to a repulsive force that accelerates movable member 37 away from first coil 47. The kinetic energy imparted on movable member 37 in this manner is sufficient to move movable member 37 to its second location adjacent to second drive coil 48.
The two drives 17, 18 should be operated synchronously, or at least in the same time window. A pulse generator 49 (e.g, see
In an exemplary embodiment, a concurrent operation can for example be achieved by electrically arranging the first drive coils 47 of both switches in series, as shown by the feed lines between the drives 17, 18 and pulse generator 49 in
Thus, it will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 11161924.3 | Apr 2011 | EP | regional |
