EP0591591B1 - Isolating switch with snap opening - Google Patents

Abstract

Isolating switch comprising a pivoting blade linked to a first connector, equipped with a contact hammer interacting with a contact jaw linked to a second connector, characterised in that it comprises a first contact finger (31) fixed to a first spring (32) and linked electrically to the said second connector, a second contact finger (41) fixed to a second spring (42) and linked electrically to the said second connector, the said fingers capable of coming successively into contact with an arc horn (25) extending the said hammer (14) during the operation of opening the said isolating switch, the said second finger and second spring being arranged so that the movement of opening the isolating switch tends more and more to tension the said second spring and, after a given opening travel, to cause the second finger of the arc horn to be released. <IMAGE>

Description

The present invention relates to a disconnector according to the preamble of claim 1 and in particular to high voltage disconnectors; in the following, reference will be made to a disconnector with vertical cutoff, but it should be understood that the invention also applies to other types of disconnector, in particular earthing disconnects.

A disconnector with vertical cut-off notably comprises a pivoting blade electrically connected by a first end to a first connector disposed at the top of a first insulating column, said blade carrying at its second end a hammer cooperating with a jaw electrically connected to a second connector disposed at the top of a second insulating column.

Such a disconnector has very little or no breaking capacity.

An object of the present invention is to define a disconnector having a real breaking capacity, making it possible for example to allow, without destruction of the main contacts (jaw and blade), a hundred opening operations at 450 kV and 1600 A or a few maneuvers at 730 kV and 2600 A..

Known from US Pat. No. 2,897,323, on which the preamble of claim 1 is based, a disconnector-circuit breaker assembly in which the disconnector comprises an arc horn comprising a rod cooperating with a caster. This unit cannot operate when placed in a humid and cold climate as the caster and rod are covered with ice. The relative movement of the caster and the rod does not break the ice because this mechanism works in compression. It should be noted that breaking the ice in compression requires considerable effort.

Another object of the invention is to provide a high voltage disconnector capable of operating in severe climatic conditions.

Most high voltage disconnectors have the disadvantage of having electromagnetically radiating arc horns, which results in the emission of radio frequencies which can cause interference with normal radio emissions.

Another object of the invention is to provide a disconnector having no parasitic emissions.

Another object of the invention is to provide a disconnector of economical construction.

All of the aforementioned aims are achieved by the high voltage disconnector of the invention which comprises a pivoting blade connected to a first connector, provided with a contact hammer cooperating with a contact jaw connected to a second connector and characterized in that '' it comprises a first contact finger fixed to a first spring and electrically connected to said second connector, a second contact finger fixed to a second spring and electrically connected to said second connector, said fingers being able to come successively into contact with an arc horn extending said hammer during an opening operation of said disconnector, said second finger and second spring being arranged so that the opening movement of the disconnector tends to bandage said second spring more and more and to escape, after a stroke of given opening, said second finger of the bow horn, the fingers being arranged perpendicular to the blade, the electrical contact ique between the first finger and the bow horn being, when the disconnector is in the closed position, at the lower part of the bow horn.

In a particular embodiment in which the disconnector is of the type in which an opening operation begins with a rotation of the hammer on itself which causes a reduction or cancellation of the contact force between said hammer and said jaw, said first finger and said first spring are arranged so that, during this reduction or cancellation, said first finger is in contact with said bow horn, said first spring ensuring sufficient contact pressure until the bow horn comes into contact with said second finger with sufficient force.

Preferably, the bow horn is removable and made of silver copper.

The contact fingers, the springs and the spring support rods are for example made of stainless steel.

• la figure 1 est une vue partielle en élévation d'un sectionneur à coupure verticale selon l'invention, représenté pendant une opération d'ouverture,
• la figure 2 est une vue de côté du même sectionneur au même instant de fonctionnement que celui de la figure 1.
• la figure 3 est une vue en élévation du même sectionneur en position fermée,
• la figure 4 est une vue de côté du même sectionneur, en position fermée,
• la figure 5 est une vue en élévation du même sectionneur, en phase d'ouverture, dans une position intermédiaire à celle des figures 1 et 3,
• la figure 6 est une vue de côté du même sectionneur au même instant de fonctionnement que celui de la figure 5.

The invention will be better understood from the description given below of an example of implementation of the invention, with reference to the appended drawing in which:

• FIG. 1 is a partial elevation view of a vertical cut-off switch according to the invention, shown during an opening operation,
• FIG. 2 is a side view of the same disconnector at the same operating instant as that of FIG. 1.
• FIG. 3 is an elevation view of the same disconnector in the closed position,
• FIG. 4 is a side view of the same disconnector, in the closed position,
• FIG. 5 is an elevation view of the same disconnector, in the opening phase, in a position intermediate to that of FIGS. 1 and 3,
• FIG. 6 is a side view of the same disconnector at the same operating instant as that of FIG. 5.

In FIG. 1, the reference 1 designates a metal strip pivoting in a vertical plane around an axis 2 placed at the end of a first insulating column 3 of which only the upper part is shown. The movement of the blade is ensured by a pivoting column 4 provided with a mechanism not shown allowing its rotation around its axis 4A. The transmission of the rotational movement from the column to the blade 1 is ensured by a rod 6, articulated at one of its ends to a ball joint 7 secured to the blade 1 and articulated at its other end by an axis 8 to an arm 9 secured to the pivoting column 4.

The blade 1 is electrically connected to a first connector 10 by a metal piece 11 serving as a pivot for the axis 2.

The blade 1, which constitutes the movable contact of the disconnector, carries, at its end opposite to the axis 2, a contact hammer 14, cooperating with a jaw 15, which constitutes the fixed contact of the disconnector and which is carried by a second insulating column 16. The hammer 14 can carry two opposite protuberances 14A and 14B which allow, when the disconnector is in the closed position, to obtain, after a 90 degree rotation of the blade around its axis, very tight contact with the jaws and, conversely, to allow a contact of force reduced or even canceled before this rotation. The means for obtaining this rotation has not been shown, since it is well known to those skilled in the art and is not part of the present invention.

The jaw is made up of two rows 15A and 15B of contact pieces each formed by a curved blade and fixed to a jaw support 17. This support is electrically connected to a second connector 18. The references 21 and 22 designate shield rings -waves at the potential of the second connector.

According to the invention, the hammer 14 is extended by a metal part, called an arc horn, referenced 25. This arc horn cooperates, in the manner which will be described later, with two arcing contact fingers 31 and 41 which are now described.

The arcing contact finger 31 is a metal part placed at the end of a support formed in the form a spring 32 having several turns and mechanically fixed to the jaw support 17 by means of a threaded rod 33 and nuts 34 and 35. A metal braid 36 ensures good electrical contact between the contact finger 31 and the support jaw. The spring 32 is adjusted so that the contact finger 31 is substantially horizontal when it is not in contact with the arcing horn 25. The arcing contact finger 31 is arranged so that, when the disconnector is in the closed position (Figures 3 and 4), the arcing horn pushes the contact finger 31 down against the action of the spring. It is noted that the contact finger 31 is in contact with the lower part of the arc horn 25, therefore sheltered from the ice. The electrical contact is therefore always ensured, with a force of several kilograms due to the spring 32.

The arcing contact finger 41 is a metal part placed at the end of a support constituted in the form of a spring 42 having several turns and mechanically fixed to the jaw support 17 by means of a threaded rod 43 and d 'nuts 44 and 45. A metal braid 46 ensures good electrical contact between the contact finger 41 and the jaw support. The spring 42 is adjusted so that the contact finger 41 is substantially horizontal when it is not in contact with the arcing horn 25. The arcing contact finger 41 is arranged so that, when the disconnector is in the closed position (Figures 3 and 4), it is located above the arc horn and without contact with the latter.

The contact fingers 31 and 41 are placed offset from one another, following the direction of the bow horn.

The operation of the disconnector is as follows:

1. Opening operation

In the closed position (Figures 3 and 4), the current flows through the connector following the path passing through the connector 18, the jaw 15, the hammer 14, the blade 1, the pivot 11 and the connector 10. The contactor, when opening, begins by rotating it 90 degrees, which separates the hammer from the contact fingers; the current is derived on the arc horn 25 which is in contact with the contact finger 31 put under pressure by the spring 32 (FIG. 6). The spring 32 makes it possible to exert a contact force of approximately 40 N, which is sufficient to ensure the passage of the current. As explained, the electrical contact between the parts 31 and 25 is always ensured because it is made at the lower part of the bow horn 25, therefore sheltered from the ice. When the hammer rotates, the contact finger 31 tears off the glass which may be on the lateral part of the bow horn, and this is all the more easily as the contact finger 31 works not in compression, but shear. The electrical contact remains ensured between the elements 31 and 25 as long as they remain in mechanical contact.

After completing its rotation, the hammer 14 begins to lift. The horn 25, remaining in contact with the finger 31 thanks to the action of the spring 32, comes into contact with the finger 41. The contact between the horn 25 and the finger 41 is made on the lower part of the finger which is therefore relatively protected ice.

Continuing its lifting, the bow horn 25 leaves the finger 31, but the passage of the current remains ensured by the finger 41. The finger 41 is driven by the bow horn in its course (FIG. 2), by bandaging more and more the spring 42 .; then, the finger 41 escapes the horn 25. This escape action is rapid because the spring has been strongly bandaged.

As a result, the breaking arc is quickly extinguished since a sufficient isolation distance is obtained very quickly. There is no risk of re-priming and wear of the parts is limited.

Advantageously, the bow horn, made of silver-plated copper, is removable, so that it can be easily replaced.

The contact fingers 31 and 41, the springs 32 and 42 and the rods 33 and 43 supporting the springs are preferably made of stainless steel.

The orientation of the fingers 31 and 41, in planes substantially perpendicular to the plane of movement of the cutting blade, makes it possible, for voltages greater than 230 kV, to direct the magnetic waves towards the windscreen rings 21 and 22, this which reduces the risk of radio interference.

Closing operation

The previous operations are carried out in reverse; during the descent of the blade 1, the arc horn comes into contact with the finger 41; then the latter escapes the arc horn while the latter is already in contact with the finger 31. The rotation of the hammer allows the scraping of the finger 31 by the horn 25, which ensures good electrical contact for a subsequent operation of 'opening.

The invention applies to high voltage disconnectors.

Claims (5)

1. A section switch comprising a pivoting blade (1) connected to a first connector (10), the blade being provided with a contact hammer (14) for co-operating with contact jaws (15) connected to a second connector (18). the section switch being characterized in that it includes a first contact finger (31) fixed to a first spring (32) and electrically connected to said second connector (18), a second contact finger (41) fixed to a second spring (42) and electrically connected to said second connector (18), said fingers (31, 41) being suitable for coming successively into contact during an opening operation of said section switch with an arcing horn (25) that extends said hammer (14), said second finger (41) and second spring (42) being disposed so that the opening movement of the section switch causes ever-increasing amounts of energy to be stored in said second spring (42) and causing said second finger (41) to escape from the arcing horn (25) after a given opening stroke, the fingers (31, 41) being disposed perpendicularly to the blade (1), electrical contacts between the first finger (31) and the arcing horn (25) taking place while the section switch is in its closed position via the bottom portion of the arcing horn (25).
2. A section switch according to claim 1, characterized in that when the section switch is of the type in which an opening operation begins with the hammer (14) rotating about its own axis, thereby reducing or eliminating the contact force between said hammer and said jaw (15), said first finger (31) and said first spring (32) are disposed in such a manner that during said reduction or elimination, said first finger (31) is in contact with said arcing horn (25), said first spring (32) providing sufficient contact pressure until the arcing horn comes into contact with said second finger (41) with sufficient force.
3. A section switch according to claim 1, characterized in that the arcing horn (25) is removable.
4. A section switch according to claim 1, characterized in that the arcing horn (25) is made of silver-plated copper.
5. A section switch according to claim 1, characterized in that the contact fingers (31, 41), the springs (32, 42), and the spring supporting rods (33, 43) are all made of stainless steel.

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