EP2945176B1 - Medium voltage switchgear using the technique of break in vacuum - Google Patents

Description

TECHNICAL AREA

The present invention relates to a medium voltage electrical switchgear comprising in phase at least two switching devices, each switchgear having a disconnector placed on an electrical line, said disconnector comprising a first so-called fixed contact and a second so-called mobile contact. one of these two contacts being electrically connected to a current carrying bar, while the other contact is connected, respectively for all the switching devices, to different electrical circuits, each switching device comprising means for carrying out the disconnect function and means to ensure the break function

STATE OF THE PRIOR ART

The main manufacturers of medium voltage switches, the technology of mechanical separation of electrical contacts in the SF6, have been used since the 1970s in order to cut the rated currents of the switches.

This solution has many advantages as regards the compactness of the devices, their cost and their performance. These advantages are mainly due to the exceptional physical properties of SF6: dielectric strength, thermal conductivity, chemical stability, electronegativity, non-toxicity.

However, SF6 gas has the disadvantage of being one of the most important greenhouse gases.

It is also known to use vacuum bulbs, which can cut large currents without necessarily being placed in the SF6, but they are never used for switch functions because of their very high cost.

The patent is known FR 2937786 describing a principle to reduce the cost of this technology. The device described in this patent includes a branch on which a vacuum bulb providing the cut is placed. This bypass is inactive in steady state and traversed by the electric current only when the disconnector has begun its opening movement, by a gradual transfer of the current from the main line to the bypass. As the bulb is generally at rest, it no longer has to be dimensioned to the electrical and dielectric stress constraints in steady state. This type of system can be used for all switches in the same tank and for all phases.

However, this type of system does not allow, in terms of cost, to approach the costs of switches using SF6 gas.

The document EP 2 565 897 discloses a switchgear apparatus corresponding to the preamble of claim 1.

SUMMARY OF THE INVENTION

The present invention provides a medium voltage electrical switchgear apparatus that can be implemented without SF6 while having a reduced cost of manufacture and use.

For this purpose, the subject of the present invention is a medium-voltage electrical cut-off apparatus of the kind mentioned above, this apparatus being characterized in that it comprises a bypass circuit on which a vacuum bulb providing the cut-off is placed, said bulb characterized in that it is capable of being actuated by means of one or the other of several actuating means associated respectively with the different disconnectors, so that the bypass is inactive in steady state, and traversed by the electric current only. when one of the disconnectors has begun its opening movement, by a progressive transfer of current from the line comprising the disconnector being opened to the branch line, and in that the movable parts of the aforementioned actuating means are mechanically and electrically connected to each other by a connecting rod, so that the actuation of one said actuating means causes actuation of all the actuating means and that the progressive transfer of the current of the line of the disconnector being opened towards the line of derivation is carried out by the bead portion between the actuating means associated with the disconnector during opening and this branch line.

Thanks to these characteristics, a medium voltage electrical equipment is produced with a reduced cost making it possible to avoid the use of SF6 gas.

According to another characteristic, at least one of the aforementioned disconnectors is of the rotary type or mu in translation.

According to another particular characteristic, the or each aforementioned disconnector is associated with an actuating means comprising a bar portion connected in an articulated manner to the vicinity of one of its ends, on a fixed support of the apparatus, and between its two ends to the aforementioned rod, said bar portion cooperating at its second end with the movable contact of said disconnector.

According to another particular characteristic, all the disconnectors are of the rotary type and are operated in the same direction of rotation.

According to a particular embodiment, the aforementioned branch circuit comprising the vacuum interrupter is associated with one of the switching devices, the actuating means associated with the disconnector of this switching device being connected directly to the movable contact of the ampoule. , the fixed contact of the bulb being mechanically and electrically connected to the transport bar of the aforementioned current at a point corresponding substantially to the point of connection of the corresponding line of the disconnector to said bar.

According to another embodiment, the aforementioned branch circuit comprising the vacuum interrupter is disposed away from the switching devices, the various actuating means associated respectively with the different disconnectors being mechanically and electrically connected to the drive device of the movable contact of the bulb.

According to a particular feature, this apparatus comprises three cutting devices arranged side by side, and the bulb is associated with the cutoff device located in the middle of the other two.

According to a particular characteristic, one or each switching device is a medium voltage electrical switch.

BRIEF DESCRIPTION OF THE DRAWINGS

• Les figures 1 à 4 illustrent de manière schématique un appareillage de coupure électrique moyenne tension, selon une réalisation particulière de l'invention, comportant trois interrupteurs, dans différentes positions,
• La figure 1 illustre cet appareillage dans une position fermée de tous les interrupteurs,
• La figure 2 illustre cet appareillage pendant la commutation du premier interrupteur,
• La figure 3 illustre cet appareillage après la commutation, la totalité du courant passant à travers l'ampoule,
• La figure 4 illustre cet appareillage en position ouverte du premier interrupteur, pendant la coupure à travers l'ampoule, et
• La figure 5 illustre cet appareillage, le premier interrupteur étant en position de sectionnement de la tension,

But other advantages and features of the invention will become more apparent in the detailed description which follows and refers to the accompanying drawings given solely by way of example and in which:

• The Figures 1 to 4 schematically illustrate a medium voltage electrical switchgear according to a particular embodiment of the invention, comprising three switches, in different positions,
• The figure 1 illustrates this apparatus in a closed position of all the switches,
• The figure 2 illustrates this apparatus during the switching of the first switch,
• The figure 3 illustrates this apparatus after switching, all of the current passing through the bulb,
• The figure 4 illustrates this apparatus in the open position of the first switch, during the break through the bulb, and
• The figure 5 illustrates this apparatus, the first switch being in the voltage disconnection position,

DETAILED DESCRIPTION OF A PREFERRED PARTICULAR EMBODIMENT OF THE INVENTION

In the figures, there is shown a medium voltage electrical panel T comprising, for each of the electrical phases of the network, three electrical switches 1,2,3 mounted next to each other respectively on three electrical lines a, b , c parallel to each other, and extending in a direction substantially perpendicular to the longitudinal direction of an electrical distribution bar 4.

In this particular embodiment, the first two switches 1,2 form the secondary distribution loop while the third switch 3 is a power switch of the electrical device of a user.

Each switch 1,2,3 comprises a disconnector 5,6,7 having a fixed contact 5a, 6a, 7a electrically connected to the bar 4 and a movable contact 5b, 6b, 7b formed by a rotary knife electrically connected to an electrical circuit .

The second 2 of the switches is associated with a bypass circuit 8 comprising a vacuum interrupter 9 having a fixed contact 9a electrically connected to the bar 4, at a point situated substantially at the same level of the bar as the point of connection of the fixed contact. 6a of the second disconnector 6 to the bar 4, and a movable contact 9b mechanically and electrically connected to a so-called second actuating means 13, which is mechanically and electrically connected to a first 12 and a third 14 actuating means, as this will be explained in the following.

These three actuating means 12, 13, 14 are each constituted by a bar portion 15, 16, 17 mounted articulated by one of its ends, on a fixed support 20 of the frame of the apparatus and by its opposite end. , to a rod 18 of mechanical and electrical connection slidably mounted relative to said frame in a direction extending substantially parallel to the longitudinal direction of the bar 4.

The movable contact support 9b of the bulb 9 is also hingedly connected to the bar portion 16 associated with the second disconnector 6 at a point situated between the two ends of this bar portion 16, so that the rotation counterclockwise of this bar portion 16 causes the closure of the contacts of the bulb 9.

The operation of the apparatus will be described in the following with reference to the figures.

In normal operation as shown on the figure 1 , all the switches 1,2 and 3 are closed in order to supply the secondary distribution loop formed by the first two switches 1,2 and the customer power switch constituted by the third switch 3. In this example embodiment , it will be considered that the first switch 1 is powered directly by the network and that it feeds itself a downstream portion of the network which is located on its right. As regards the first switch 1, the path of the current is represented by the arrows. The current flowing through the other two switches is not shown.

At the beginning of the opening of the first switch 1 as illustrated on the figure 2 a switching of the current occurs, during which the current coming from the moving contact 5b of the first disconnector 5 will pass through both the fixed contact 5a of the first disconnector and the bar portion 16 of the actuating means. said second associated with the second disconnector 6, through the first bar portion 15, the connecting portion 18a of the rod 18 located between the two bar portions 15,16 associated respectively with the first two disconnectors, then through the second portion 16 and then moves towards the bulb 9 to join the busbar 4. This rotational movement of the movable contact 5b of the first disconnector 5 in the clockwise direction has generated a rotation in the counterclockwise direction of the bar portions, and in particular the second bar portion 16, which causes the movable contact of the vacuum bulb in a closed position.
When the opening of the first switch 1 is continued, the moving contact 5b of this first disconnector 5 completely separates from its associated fixed contact 5a, as illustrated in FIG. figure 3 . During this phase, the current then passes only through the contacts of the vacuum interrupter 9.
When the movable contact 5b of the disconnector 5 is sufficiently far from its associated fixed contact 5a, the second actuating means 13 associated with the second disconnector 6 will then begin to open the contacts of the vacuum interrupter, thanks to to a system not described here but described in the document FR 2,937,786 , which will quickly have the effect of cutting off the electrical current, as illustrated on the figure 4 .
During further opening of the switch, the movable contact 5b of the disconnector 5 will then be released from the bar portion 15 of the first actuating means 12, until reaching its final opening position which will allow to isolate the voltage between the upstream and the downstream of the switch, as illustrated on the figure 5 . During this step, the bar portions 15, 16, 17 will then resume their initial position represented on the figure 1 , thanks to the presence of non-illustrated return springs.
The closing operation will be performed by operating the disconnector in the opposite direction, which will not produce an effect on the bar portion of the corresponding actuating means, until the contact of the movable contact 5b with the fixed contact 5a.
The operation of the other two switches 2,3 will not be described because it is the same as that of the first switch 1.

The invention may advantageously be used on boards comprising between 2 and 5 switches.
Moreover, one can also imagine integrating this device comprising the vacuum bulb anywhere in a tank (and therefore not necessarily associated with a switch). In this case, mechanical actuation means will then be advantageously placed on all the switches of the cell, these being then electrically and mechanically connected to the drive device of the movable contact of the bulb. Although more cumbersome, this alternative will be interesting in the case where one would not wish to electrically constrain the area of the switches. This may for example reduce the width of the cell at the expense of its height, which can sometimes be less critical vis-à-vis the footprint of the cell.

Thanks to the invention, the cost of breaking in vacuum is considerably reduced by the fact that only one system such as that described in the patent cited above, per phase, is used in the distribution board, the others functions only equipped with mechanical actuation systems alone. In order to allow the breaking of the current on a switch which is not equipped with vacuum bulbs, a mechanical connection (bar) connects the different moving parts of the actuating systems to each other. Thus, when acting on a system, all other systems (including the one comprising the vacuum bulb) are actuated simultaneously.
Of course, the invention is not limited to the embodiment described and illustrated which has been given by way of example.
For example, although in the embodiment previously described and illustrated, the complete cutoff system comprising the vacuum interrupter has been added to the middle switch, it could have been associated with another of these switches.

Claims (8)

1. Medium voltage electric switching device comprising at least two switching devices per phase, each switching device comprising an disconnector placed in an electric line, said disconnector comprising a first contact called a fixed contact and a second contact called a moving contact, one of these two contacts being electrically connected to a current carrying bar, whilst the other contact is connected, respectively for all of the switching devices, to different electrical circuits, each switching device comprising means for carrying out the function of disconnection and means for providing the switching function, and a branch circuit (8) in which a vacuum interrupter (9) providing the switching is placed, said vacuum interrupter (9) being able to be actuated by the intermediary of one or other of several actuating means (12, 13, 14) respectively associated with the different disconnectors (5, 6, 7), in such a way that the branch is inactive in ongoing operating conditions, characterized in that the branch is traversed by the electric current only when one of the disconnectors (5, 6, 7) has started it movement of opening, by a progressive transfer of current from the line comprising the disconnector (5) in the process of opening to the branch line (8), and in that the moving parts of the aforesaid actuating means (12, 13, 14) are mechanically and electrically connected to each other by a connecting rod (18), in such a way that the actuation of one of the aforesaid actuating means (12, 13, 14) brings about the actuating of all of the actuating means and that the progressive transfer of the current from the line of the disconnector (5) in the process of opening to the branch line (8) is carried out through the portion (18a) of rod (18) situated between the actuating means (12) associated with this disconnector (5) in the process of opening and this branch line (8).
2. Device according to Claim 1, characterized in that at least one of the aforesaid disconnectors (5, 6, 7) is of the rotary type or is driven in translation.
3. Device according to claim 2, characterized in that the aforesaid disconnector or each of them (5, 6, 7) is associated with an actuating means (12, 13, 14) comprising a portion of bar (15, 16, 17) connected in an articulated manner in the vicinity of one of its ends to a fixed support (20) of the device, and between its two ends to the aforesaid rod (18), said portion of bar cooperating by its second end with the moving contact (5b, 6b, 7b) of said disconnector (5, 6,7).
4. Device according to any one of the preceding claims, characterized in that all of the disconnectors (5, 6, 7) are of the rotary type and are driven in the same direction of rotation.
5. Device according to any one of the preceding claims, characterized in that the aforesaid branch circuit (8) comprising the vacuum interrupter (9) is associated with one of the switching devices (1, 2, 3), the actuating means (12, 13, 14) associated with the disconnector (5, 6, 7) of this switching device being directly connected to the moving contact (9b) of the tube (9), the fixed contact (9a) of the tube (9) being mechanically and electrically connected to the aforesaid current carrying bar (4) at a point substantially corresponding to the point of connection of the line b corresponding to the disconnector (6) to said bar (4).
6. Device according to any one of claims 1 to 4, characterized in that the aforesaid branch circuit (8) comprising the vacuum interrupter (9) is disposed away from the switching devices (1, 2, 3), the different actuating means (12, 13, 14) respectively associated with the different disconnectors (5, 6, 7) being mechanically and electrically connected to the driving device of the moving contact of the tube (9).
7. Device according to any one of the preceding claims, characterized in that it comprises three switching devices (1, 2, 3) disposed side by side, and in that the tube (9) is associated with the switching device (2) situated in the middle of the other two (1, 3).
8. Device according to any one of the preceding claims, characterized in that one or each switching device (1, 2, 3) is a medium voltage electric switch.

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