EP2051272A1 - Set of disconnecting switches for a medium- and high-voltage electric substation in a metal enclosure - Google Patents

Abstract

The assembly has a movable element or contact (8) including two electrically conducting parts such as tube shaped outer and rod shaped inner parts (8.1, 8.2) which are axially integrated together in direction for earthing an electrode (4). The parts are axially disintegrated from one another. The part (8.2) is displaced in another direction by releasing an elastic energy storage unit i.e. helical spring (28), which is compressed during displacement in the former direction while being electrically connected to the part (8.1) for closing an earthing disconnector earthing the electrode (2). The elastic energy storage unit is made of electrically insulating material e.g. glass fiber loaded epoxy. An independent claim is also included for a method for selecting and earthing a metal enclosed high and medium voltage distribution station.

Description

TECHNICAL FIELD AND PRIOR ART

The present invention relates to an isolation disconnector assembly, a slow earth disconnector and a fast earth disconnector for a medium and high voltage metal-encased electrical substation.

The metal-jacketed medium and high voltage distribution stations comprise a sealed envelope filled with a dielectric gas, SF6 type in which are generally arranged, circuit breakers, isolating disconnectors. The station is connected to departures by overhead line or cable via crossings or cable boxes. For reasons of operation and personnel safety in case of intervention on the substation, the disconnector located on the line feeder is framed on the side of the circuit breaker of a earthing switch allowing earthing at a relatively fast speed. slow, called slow earthing switch having, by its speed, no closing power on short circuit and the side of the line feeder of a earthing switch allowing a grounding next a relatively high speed, called fast earthing switch to close or not on a short circuit current.

Usually, each of the disconnectors is controlled individually. For example, the document FR 1 487 723 discloses an isolation isolating switch and two individually controlled earthing switches.

The document EP 1 361 633 also discloses metal encased substations in which control of the isolating switch and control of the earthing switch are combined. However, the control of the fast earthing switch remains independent. This type of item can reduce the cost compared to stations with an individual command for each disconnector, however the separate command of the fast earthing switch involves significant additional cost.

It is therefore an object of the present invention to provide a metal-encased post offering a great compactness and the cost of which is reduced.

STATEMENT OF THE INVENTION

The above stated purpose is achieved by a metal jacketed station in which the isolation disconnector, the slow earthing switch and the fast earthing switch have a single control.

In other words, a movable conductive element common to the three disconnectors is used.

According to the invention, the opening of the isolating switch and the grounding of each of the electrodes forming the isolation disconnector is effected by the displacement of two interlocked elements for opening the isolating switch and for closing the slow earthing switch, and these two elements becoming mobile. relative to each other while maintaining their electrical contact for closing the fast earthing switch.

In one embodiment, the conductive element providing contact between the line-side electrode and the circuit-breaker-side electrode is in one piece, the fast grounding of the line-side electrode being effected by this element.

In another embodiment, the conductive element ensuring the contact between the line-side electrode and the circuit-breaker electrode is composite, ie in two parts able to slide relative to one another, one of the two parts contacting the line-side electrode to ground it.

The present invention therefore mainly relates to a set of disconnectors for medium and high voltage metal-enclosed distribution station comprising a first electrode, a second electrode and a third grounding electrode, arranged in this order along a longitudinal axis, a movable element able to move along said longitudinal axis, said movable conductive element comprising a first longitudinal end intended to bring the first and the second electrode into contact, a second end longitudinal member intended to come into engagement with axial displacement means, the mobile element comprising a first part and a second electrically conductive part, axially fixed in a first direction to ground the second electrode and able to disengage axially, the second part being able to move in a second direction, while maintaining electrical contact with the first part, to allow the closure of the earthing switch of the first electrode.

According to the present invention, the displacement of the movable element in the first direction can be obtained by activation of the displacement means and the displacement of the second part of the movable element in the second direction can be obtained by the release of a compressed elastic means when moving in the first direction.

The set of disconnectors according to the present invention may comprise means for securing the first and second parts of the movable element, the annihilation of the securing obtained by the securing means and the release of the load of the elastic means thus compressed is obtained automatically by an additional relative displacement in the first direction of at least a portion of the movable member.

In a first embodiment, the first part of the movable element is in direct contact with the displacement means and is partially made of electrically conductive material coming into electrical contact with the third electrode for grounding the first and second electrodes.

The first part may comprise a larger diameter portion of electrically conductive material and an insulating portion of smaller diameter, the contact with the third electrode being obtained by contact between the larger diameter portion and the third electrode.

The elastic means is for example mounted in reaction between a radial wall of the second electrode, and an axial end of the second portion interposed between said radial wall of the second electrode and the first electrode, the second electrode comprising a radially outer tube and a radially inner tube connected by said radial wall, the elastic means being disposed between the two tubes concentrically.

The securing means comprise for example a finger mounted radially in a cage secured to the tube of the second part, the connection between the second part and the first part being obtained by cooperation of a radially inner end of the finger with a groove made in the outer face of the tube of the first part, said finger being resiliently biased towards the longitudinal axis by a resilient means mounted radially in the outer tube via a pusher.

The radially outer tube of the second electrode may comprise on an inner face a groove, said groove making it possible to securing the second portion to the spring cage by penetrating a radially outer end of the finger into said groove and by cooperation of the other radially inner end of the finger with the outer surface of the first distinct portion of the groove, the finger being biased radially away from the axis by an elastic means mounted in the cage, the load of the second resilient means being less than that of the first elastic means.

The first part advantageously comprises at an upstream end in the first direction, a slope oriented towards the first electrode, the release of the load of the elastic means being effected by a sliding of the radially inner end of the finger on said slope, by a radially moving the finger inward and an outlet of the radially outer end of the groove finger, the second part then being detached from the second electrode.

In a second embodiment, the first part comprises an end intended to come into electrical contact with the first and the second electrode and a second longitudinal end engaged with the displacement means, and the second part comprises a longitudinal first end intended to come into electrical contact with the first and the second electrode.

The first part is for example radially outer and surrounds the second radially inner part, the second end of the first part being made of electrically insulation and said second portion being adapted to be secured axially to the first part by securing means, said second portion having an electrically conductive end on the side of the first electrode and an electrically insulating end on the side of the third electrode.

The elastic means is advantageously mounted in reaction between the second radially inner portion and the third electrode.

The elastic means is advantageously made of electrically insulating material and can thus be disposed at least partly in the sealed envelope in abutment against the sealed envelope and the movable contact.

The third electrode forms for example an axial bottom of the sealed envelope provided with a central passage whose periphery is intended to come into contact with the outer part of the movable contact.

The securing means are in a variant disposed outside the sealed envelope in a cylindrical envelope open at one end and bordering the central passage of the grounding electrode.

The securing means may comprise a radially movable finger and an elastic return means towards the longitudinal axis, said radial finger being resiliently biased towards the longitudinal axis, said radial finger being mounted on the first portion and the second radially inner portion comprising a radial passage for receiving the radial finger, the cylindrical envelope being provided a bottom of which projects a central finger along the longitudinal axis adapted to come to urge the radial finger penetration into a bore in the second part and into which said passage to escape from said passage.

The securing means may comprise a radially movable finger and an elastic return means mounted in reaction in a cage between one end of the cage and the radial finger, said radial finger being resiliently biased towards the longitudinal axis, said radial finger being mounted on the first portion and the second radially inner portion having a radial passage for receiving the radial finger, and wherein the third electrode comprises at a downstream end in the second direction a bottom which projects a central finger on the longitudinal axis adapted to to urge the radial finger through a bore in the second portion and into which said passage to escape from said passage.

The third electrode advantageously comprises axial guiding means of the first and second parts of the movable element, also forming a support for the elastic means.

The guiding means comprise for example a tube integral with the bottom and coming to be interposed radially between the first portion and the second radially inner portion, said tube having an axial slot receiving the radial finger (30).

The second radially inner portion may comprise at a longitudinal end downstream of the passage in the first direction a slope oriented away from the passage intended to cooperate with the tip of the radial finger to allow the radial finger to slide radially outwards and penetrate the passage to secure the first and second part of the conductive element.

Whatever the embodiment The displacement means are, by way of non-limiting example, the rack type cooperating with a toothed wheel, levers or worm.

The elastic means may be made of epoxy filled with glass fibers.

The speed of movement of the movable element in the first direction is advantageously between 0.02 m / s and 0.2 m / s, and the speed of displacement of the second part of the movable element to connect the first and the third electrode is advantageously between 2 m / s and 8 m / s.

The first electrode may be connected to a high or medium voltage line or a cable feeder and the second electrode may be connected to a circuit breaker.

Advantageously, the set of disconnectors according to the invention may comprise means for preventing a relative rotational movement between the movable element and the first, second and third electrode and between the first and the second part.

The present invention also relates to a medium and high voltage station in a metal envelope, comprising a set of disconnectors according to the present invention, wherein the metal casing is connected to the earth and the third electrode and connected to the metal casing.

1. a) déplacement de l'élément mobile dans un premier sens pour interrompre la connexion électrique entre la première et la deuxième électrode,
2. b) déplacement de l'élément mobile d'une course supplémentaire dans le premier sens pour connecter électriquement la deuxième et la troisième électrode,
3. c) déplacement d'au moins une partie de l'élément mobile d'une course encore supplémentaire dans le premier sens pour libérer au moins la deuxième partie de l'élément mobile, celle-ci se déplaçant dans le deuxième sens et connectant électriquement la première et la troisième électrode.

The present invention also relates to a method for severing and grounding a medium and high voltage substation, said substation comprising a first electrode, a second electrode and a third grounding electrode, arranged according to this method. arranging, along a longitudinal axis, a movable member adapted to move along said longitudinal axis, said movable member having a first longitudinal end for contacting the first and second electrodes, a second longitudinal end intended to engage with axial displacement means, said method comprising the steps of:

1. a) moving the movable element in a first direction to interrupt the electrical connection between the first and the second electrode,
2. b) moving the movable member of an additional stroke in the first direction to electrically connect the second and the third electrode,
3. c) moving at least a portion of the movable member an additional stroke in the first direction to release at least the second portion of the movable member, which moves in the second direction and electrically connecting the first and the third electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 est une vue en coupe longitudinale d'un ensemble de sectionneurs selon un premier mode de réalisation,
• les figures 2A à 2E sont des vues en coupe longitudinale schématiques partielles de l'ensemble de sectionneurs de la figure 1 dans différents états de commande,
• les figures 3A à 3G sont des vues en coupe longitudinale schématiques partielles d'un ensemble de sectionneurs selon un deuxième mode de réalisation dans différents états de commande,
• les figures 4A à 4D sont des vues en coupe longitudinale d'un ensemble de sectionneurs selon le deuxième mode de réalisation dans différents états de commande dans lequel l'enveloppe étanche est représentée,
• la figure 5 est une vue agrandie d'un détail de la figure 4A,
• les figures 6A à 8A sont des vues en coupe longitudinale d'une variante de réalisation d'ensemble de sectionneurs selon le premier mode de réalisation dans différents états de commande,
• les figures 6B à 8B sont des vues agrandies d'un détail des figures 6A à 8A respectivement.

The present invention will be better understood with the aid of the description which will follow and the drawings in appendices on which the front and the back are respectively the left and the right, on which:

• the figure 1 is a longitudinal sectional view of a set of disconnectors according to a first embodiment,
• the Figures 2A to 2E are partial schematic longitudinal sectional views of the set of disconnectors of the figure 1 in different control states,
• the Figures 3A to 3G are partial diagrammatic longitudinal sectional views of a set of disconnectors according to a second embodiment in different control states,
• the Figures 4A to 4D are views in longitudinal section of a set of disconnectors according to the second embodiment in different control states in which the sealed envelope is shown,
• the figure 5 is an enlarged view of a detail of the Figure 4A ,
• the Figures 6A to 8A are views in longitudinal section of an alternative embodiment of the set of disconnectors according to the first embodiment in different control states,
• the Figures 6B to 8B are enlarged views of a detail of Figures 6A to 8A respectively.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

The sets of disconnectors according to the present invention have substantially a symmetry of revolution about a longitudinal axis X.

In the following description, the forward movement corresponds to a movement in a closing direction of the isolating and closing switch of the fast earthing switch. The rearward movement corresponds to a movement in the opening direction of the isolating and closing switch of the slow earthing switch.

On the figure 1 a first embodiment of a set of isolating switches combining an isolating disconnector, a slow grounding disconnector, also called slow MALT and a fast earthing disconnector, also called fast MALT, can be seen.

The set of disconnectors is intended to be arranged in a sealed metal casing (not shown) filled with a gas with a high dielectric strength, for example sulfur hexafluoride (SF ₆ ), dry air or air. nitrogen (N2), this set is interposed, for example between a circuit breaker (not shown) and a high or medium voltage line (not shown) in a substation starting line.

The set of disconnectors comprises a first electrode 2 connected to a high or medium voltage line or cable outlet, a second electrode 4 connected to the circuit breaker, and a third electrode 6 to ground. In the example shown, the third electrode 6 is connected to the envelope which is itself grounded.

According to the present invention the three electrodes 2, 4 and 6 are arranged in this order along a longitudinal axis X of the set of disconnectors.

On the Figures 2A to 2E , we can see the set of disconnectors of the figure 1 in different operating states.

The first X axis electrode 2 comprises at an axial end 2.1 facing the second electrode 4 a central cavity 10 forming an electrical contact made of a material allowing the establishment of an electric arc and an annular cavity 12 surrounding the cavity central 10 forming an electrical contact for the passage of the permanent current.

The second electrode 4 comprises an X-axis tube whose axial end 4.1 is opposite the first electrode 2.

The third grounding electrode 6 is disposed behind the second electrode 4. In the example shown, the third grounding electrode 6 has a cylindrical inner profile comprising a zone of smaller cross-section 6.1 and a smaller diameter. second zone 6.2 more large cross section, said zone of smaller cross section being on the side of the second electrode 4. But it could be expected that the third electrode is of constant section and sufficient to house an immobilization mechanism which will be described later.

The third grounding electrode 6 has at its axial end opposite the zone of smaller section 6.1 a sealed bottom 6.3.

The set of disconnectors also comprises an electrically conductive movable element 8 capable of bringing the first 2 and second 4 electrodes or the second 4 and third 6 electrodes and / or the first 2 and third 6 electrodes into electrical contact.

According to the first embodiment, the movable element 8 comprises two conductive parts 8.1, 8.2, an outer part 8.1 and an inner part 8.2 concentric to the first part 8.1.

The outer part 8.1 is of tubular shape and is intended to penetrate into the annular cavity 12 of the first electrode 2 or into the cavity 6.1 of the electrode 6 and the inner part 8.2 has the shape of a rod intended to penetrate into the central cavity 10 of the first electrode.

The outer part 8.1 is kept in electrical contact with the inner part 8.2 by means of a ring 14 projecting radially inwardly from an inner face of the outer part 8.1. An electrical contact 16 is provided on this projection 14 and a mechanical guide.

The inner part 8.2 and the outer part 8.1 are able to be joined in motion in certain operating phases of the disconnectors and able to slide relative to each other in other phases of maneuver, as we shall see by the after.

The zone of smaller section 6.1 has an inner diameter substantially equal to the outer diameter of the outer portion 8.1 of the conductive element 8. Thus, when the outer element 8.1 recedes, it comes into electrical contact with the third electrode 6 at the level of the area of smaller section 6.1.

Advantageously, this zone comprises an electrical contact corresponding to the diameter of the outer portion 8.1. In the example shown, this contact is made by a radially inwardly projecting annular projection intended to come into contact with the outer part 8.1 and to exert a radial force on the latter due to the elasticity of the material.

The outer portion 8.1 extends rearwardly towards the bottom 6.3 of the third electrode 6 by a rod 18 of tubular form.

In the example shown, the connecting rod 18 is in two parts 18.1, 18.2. The second part 18.2 carries a securing means 20 of the outer part 8.1 and the outer part 8.2 of the conductive element 8.

Part 18.1 is made of insulating material to hold the voltage between the third electrode 6 and the second electrode 4. In the example shown, the other part 18.2 is made of metal, but it could be envisaged to make it also of insulating material.

The inner portion 8.2 extends rearwardly by means of a rod 22.

The rod 22 is made in two parts, a front portion 22 'and a rear portion 22' '.

The front portion 22 'is made of insulating material to hold the voltage between the third electrode 6 which is grounded and the second electrode portion 4 which is under high voltage. The rear portion 22 "is advantageously metal for reasons of mechanical strength, but it could be provided to make it insulating material with mechanical characteristics equivalent to those of the metal.

The bottom 6.3 advantageously comprises means for axial guidance of the first 8.1 and second 8.2 parts of the conductive element 8.

In the example shown, the guide means are formed by a sleeve 24 projecting axially forward towards the first electrode 2 and an axial finger 26 projecting from the bottom towards the front. The sleeve 24 holds a spring 28 which will be described below, and the finger 26 serves as a means for allowing expansion of said spring.

The set of disconnectors also comprises an elastic energy storage means 28 disposed between a front end 24.1 of the sleeve 24 integral with the bottom 6.3 and the rod 22 extending the inner part 8.2 of the conductive element 8.

The elastic energy storage means 28 is for example formed by a helical spring mounted in reaction between the end 24 of the sleeve 24 and an annular bearing surface 22.1 projecting radially outwardly of the rod 22.

Thus a displacement of the inner part 8.2 towards the rear causes compression of the spring 28.

The immobilizing means 20 comprises a radial finger 30 axially integral with the second portion 18.2 of the rod 18 and able to move radially.

The finger 30 is biased radially elastically towards the axis X by means of a spring 32 mounted in reaction between the finger 30 and the bottom of a cage 34 fixed on the connecting rod 18.

On the Figure 2A , the radial finger 30 enters a passage 35 formed in a rear end 22.1 of the rod 22. Thus the outer part 8.1 and the inner part 8.2 are axially joined by the finger 30.

The end 22.1 of the rod 22 has an axial bore 36 into which the passage 35 opens, so that an end 30.1 of the radial finger 30 opens radially into the bore 36.

The sleeve 24 integral with the electrode 6 of grounding is interposed radially between the rod 22 of the inner portion 8.1 and the connecting rod 18 integral with the outer portion 8.2 and has an axial slot 37 in which the finger 30 slides.

The axial finger 26 secured to the third electrode 6 is intended to penetrate into the bore 36 and to cooperate with the end 30.1 of the finger 30. The axial finger 26 advantageously comprises a rounded end 26.1 facing towards the end to facilitate sliding the end 30.1 of the radial finger, it could also be beveled or pointed. As for the end 30.1, it advantageously has a pointed shape, a rounded shape or spherical cap.

The rear end 22.1 of the rod 22 advantageously comprises a slope oriented towards the bottom of the third electrode 6, intended to cooperate also with the end 30.1 of the radial finger during a closing phase of the isolating switch.

The finger 30 advantageously serves anti-rotation means of the outer portion 8.1 relative to the inner portion 8.2. However, additional means can be provided.

On the figure 1 an exemplary embodiment of the displacement means 38 of the set of rack type disconnectors can be seen.

The means 38 comprise a toothed wheel 40 meshing with an axial rack 42 on the outer surface of the connecting rod 18.

It can be provided to use a set of levers or any other means adapted to axially drive the connecting rod 18.

We will now explain the operation of such a set of disconnectors.

On the Figure 2A the isolating disconnector can be seen in the closed position, the movable element 8 ensures contact between the first electrode 2 and the second electrode 4, the radial pin 30 penetrates into the radial passage 35 and provides axial fastening of the part 8.1 and the inner part 8.2.

To open the isolating switch, an operator activates the displacement means 38, in the example shown, the toothed wheel 40 is moved in rotation and moves the connecting rod 18 axially towards the rear, driving the outer part 8.1, the part 8.2 is also displaced axially via the radial finger 30. The axial displacement of the conductive element 8 may be slow, for example of the order of 0.02 m / s to 0.2 m / s. s.

The movable element 8 deviates from the first electrode 2, the displacement means 38 stop, the isolation disconnector is then in the open position, ie the first 2 and second 4 electrodes are no longer connected electrically and are sectioning distance. In this position, none of the electrodes are grounded, as can be seen on the Figure 2B .

The disconnection distance is the minimum distance between the first 2 and second 4 electrodes necessary for the electrical insulation of the gas is sufficient to ensure the dielectric strength imposed by the standards applicable to this type of equipment.

During this first race, the spring 28 was compressed. When stopping the moving means 38, here formed by a rack system, the spring 28 is kept compressed.

To return to the position represented in Figure 2A it is sufficient to actuate the displacement means 38 in the opposite direction for the connecting rod 18 to move forward.

To close the slow earthing switch, the operator activates the moving means 38 again, the connecting rod 18 resumes its axial displacement towards the rear, as well as the outer 8.1 and inner 8.2 parts, until the outer part 8.1 enters the third electrode 6 and comes into contact with the zone of smaller section of the grounding electrode 6, as shown in FIG. Figure 2C . The second electrode 4 then comes into electrical contact with the third electrode 6 (grounding) via the outer part 8.1, the earthing switch of the second electrode 4 is closed. The spring 28 was further compressed. The maneuver can also be performed slowly, for example of the order of 0.02 m / s to 0.2m / s. The moving means 38 stop. The displacement of the inner part 8.2 thus corresponds to the closing of a slow earthing switch.

To return to the position represented in Figure 2B it is sufficient to actuate the displacement means 38 in the opposite direction for the connecting rod 18 to move forward.

To close the fast earthing switch, the operator again activates the moving means 38, the outer part 8.1 and the inner part 8.2 move back again solidly. The axial finger 26 projecting from the bottom 6.3 of the electrode 6 then enters the bore 36, comes into contact with the tip 30.1 of the radial finger 30, and pushes it radially outwards against the spring 32, as shown on the 2D figure . This radial displacement of the finger 30 causes the separation of the outer part 8.1 and the inner part 8.2.

Under the effect of the load of the spring 28, the inner portion 8.2 is pushed forward, while the outer portion 8.1 remains stationary. The inner part 8.2 enters the central cavity of the first electrode 2. However, the outer part 8.1 and the inner part 8.2 remain in electrical contact.

The first electrode 2 is then electrically connected to the ground electrode 6 via the inner part 8.2 and the outer part 8.1. The earthing switch of the first electrode 2 is then closed ( figure 2E ).

The forward movement of the inner part 8.2, during the expansion of the spring 28, is rapid and therefore the closure of the earthing switch of the first electrode 2 relative to the closing of the earthing switch the second electrode 4 is fast. The speed of closing is of the order of 2 to 8 m / s, which ensures the closing performance on short circuit. The displacement of the inner part 8.2 thus corresponds to the closing of a fast earthing switch.

Return to the position represented in Figure 2A , ie the openings of the earthing switches and the closing of the isolating switch are effected by an actuation of the displacement means 38 in a direction of movement towards the front of the connecting rod 18. The outer part 8.1 then slides forward with respect to the inner part 8.2.

The outer part 8.1 then deviates from the third electrode 6 of grounding, the electrodes 2 and 4 are no longer grounded: the earthing switches of the first 2 and second 4 electrodes are open. Then, the outer part 8.1 comes into contact with the first electrode 2, the isolating switch is then closed.

The tip 30.1 of the radial finger 30 then meets the end of the rod 22 and slides on the slope, the finger 30 is then moved radially outwards against the spring 32. Then, when it is in With regard to the passage 35, the finger moves radially towards the axis X under the effect of the spring 32. The outer part 8.1 and the inner part 8.2 are then axially fixed again.

On the Figures 6A to 8B an alternative embodiment of the first embodiment of a set of disconnectors combining an isolating switch, a slow earthing switch and a fast earthing switch can be seen. In this variant, the spring of dielectric material is disposed inside the sealed enclosure.

The set of disconnectors comprises a first electrode 202 connected to a line feeder or high or medium voltage cable, a second electrode 204 connected to the circuit breaker, and a third electrode 206 of grounding. In the example shown, the third electrode 206 is connected to the envelope which is itself grounded.

According to the present invention, the three electrodes 202, 204 and 206 are arranged in this order along a longitudinal axis X of the set of disconnectors.

The first X-axis electrode 202 comprises at an axial end 202.1 facing the second electrode 204 a central cavity 210 forming an electrical contact made of a material allowing the establishment of an electric arc and an annular cavity 212 surrounding the cavity. central 210 forming an electrical contact for the passage of the permanent current.

The second electrode 204 comprises an X-axis tube whose axial end 204.1 is opposite the first electrode 200.

The third ground electrode 206 is disposed behind the second electrode In the example shown, the third grounding electrode 206 forms an end portion of the enclosure 201, the enclosure being grounded. The grounding electrode 206 has a central passage 206.1 X axis, the periphery 206.2 is intended to come into electrical contact with a movable contact of all disconnectors to ground them. This passage also makes it possible to transmit the command for operating the disconnectors as we will see later.

The set of disconnectors also comprises an electrically conductive movable contact 208 capable of bringing the first 202 and second 204 electrodes or the second 204 and third 206 electrodes and / or the first 202 and third 206 electrodes into electrical contact.

The movable contact 208 has two conductive portions 208.1, 208.2, an outer portion 208.1 and an inner portion 208.2 concentric to the first portion 208.1.

The outer portion 208.1 is tubular in shape and is intended to penetrate the annular cavity 212 of the first electrode 202 or the central passage 206.1 of the electrode 206, and the inner portion 208.2 has the shape of a rod intended to penetrate in the central cavity 210 of the first electrode 202.

The outer portion 208.1 is held in electrical contact with the inner portion 208.2 by means of a ring 214 projecting radially inwardly from an inner face of the portion 208.1. An electrical contact 216 is provided on this projection 214 in contact with the outer wall of the inner portion 208.2.

The inner portion 208.2 and the outer portion 208.1 are able to be secured in movement in certain operating phases of the disconnectors and able to slide relative to each other in other phases of maneuver, as we shall see by the after.

The central passage 206.1 has an inner diameter substantially equal to the outer diameter of the outer portion 208.1 of the conductive element 208. Thus, when the outer portion 208.1 recedes, it enters the passage 208.1 and comes into electrical contact with the third electrode 206 at the periphery 206.2 of the central passageway 206.1.

Advantageously, this zone comprises an electrical contact corresponding to the diameter of the outer portion 208.1. In the example shown, this contact is made by a radially inwardly projecting annular projection intended to come into contact with the outer part 208.1 and to exert a radial force on the latter due to the elasticity of the material.

The outer portion 208.1 extends rearwardly by a connecting rod 218 of X-axis tubular shape.

In the example shown, the connecting rod 218 is in two parts 218.1, 218.2; the first part 218.1 is directly connected to the outer part 208.1. This is made of electrical insulating material and is inside the envelope in the closed position of the isolating switch.

The second part 218.2 carries a securing means 220 of the outer part 208.1 and the outer part 208.2 of the conductive element 208.

Part 218.1 is made of insulating material to hold the voltage between the third electrode 206 and the second electrode 204. In the example shown, the other part 218.2 may be made of insulating or conductive material.

The second portion 218.2 also cooperates with longitudinal displacement means 240 along the X axis to move the outer portion 208.1. In the example shown, it is a mechanism of the worm type, the screw passing through a bore 240.1 parallel to the X axis formed in a rear base 218.2.1 of the second part 218.2. A lever mechanism or any other suitable means for axially driving the rod 218 may be suitable.

The inner portion 208.2 extends rearwardly by a rod 222.

The rod 222 is made in two parts, a front portion 222 'connected to the inner portion 208.2 and a rear portion 222' 'connected to the front portion 222'.

The front portion 222 'is of insulating material to hold the voltage between the third electrode 206, which is grounded, and the second electrode portion 204 which is under high voltage. The rear portion 222 "is advantageously made of metal for reasons of mechanical strength, but one could plan to make it out of insulating material offering mechanical characteristics equivalent to those of the metal.

A tubular envelope 242 of axis X is provided behind the sealed enclosure 1 and receiving the securing means 220 and the displacement means 240, this envelope comprises a first longitudinal end closed by a bottom 242.1 and a second open longitudinal end 242.2 bearing against the sealed envelope 201 and surrounding the central passage 206.1 of the electrode grounded 206. The tubular envelope thus extends the sealed envelope 201.

The bottom 242.1 advantageously comprises axial guiding means of the first 208.1 and second 208.2 parts of the conductive element 208.

In the example shown, the guiding means are formed by a sleeve 224 projecting axially forward towards the first electrode 202 and an axial finger 226 projecting from the bottom towards the front. The sleeve 224 holds a spring 228 which will be described below, and the axial finger 226 serves as a means for allowing said spring to relax.

The set of disconnectors also includes an elastic energy storage means 228 to allow rapid closure of the fast earthing switch. This elastic means 228 is made of an electrically insulating material, for example made of epoxy material loaded with glass fibers, for example formed by a helical spring.

According to this variant embodiment, the latter may be arranged substantially inside the sealed envelope, in particular between a front end 224.1 of the sleeve 224 secured to the bottom 242.1 and the rod 222 extending the inner portion 208.2 of the conductive element 208. Specifically, the spring 228 is mounted in reaction between the end 224.1 of the sleeve 224 and an annular bearing surface 222.1 projecting radially outwardly of the rod 222, to be loaded when the inner portion 208.2 moves rearward.

This variant makes it possible to produce a set of very compact disconnectors axially.

The spring 228 surrounds the rod 222 of the inner portion 208.2.

In the example shown, the rear end of the spring protrudes outside the enclosure. However one could predict that the spring is entirely in the enclosure.

Thus a movement of the inner portion 208.2 rearward causes compression of the spring 228.

The immobilizing means 220 comprises a radial finger 230 axially integral with the second portion 218.2 of the connecting rod 218 and able to move radially.

The radial finger 230 is biased radially elastically towards the axis X by means of a spring 232 mounted in reaction between a shoulder 230.1 formed in the periphery of the radial finger 230 and a plate 234 side fixed to the connecting rod 218 traversed by a tail 230.2 of the radial finger 230.

On the Figures 6A and 6B , the radial finger 230 enters a passage 235 formed in a rear end 222.1 of the rod 222. Thus the outer portion 208.1 and the inner portion 208.2 are axially secured by the finger 230.

The end 222.1 of the rod 222 has an axial bore 236 into which the passage 235 opens, so that an end 230.3 of the radial finger 230 opens radially into the bore 236.

The sleeve 24 integral with the ground electrode 206 is interposed radially between the rod 222 of the inner part 208.1 and the connecting rod 218 integral with the outer part 208.2 and comprises an axial slot 237, in which the radial finger 230 slides.

The axial finger 226 integral with the third electrode 206 is intended to penetrate into the bore 236 and to cooperate with the end 230.3 of the finger 230. The axial finger 226 advantageously comprises a rounded end 226.1 facing towards the end to facilitate the sliding the end 230.3 of the radial finger 230, it could also be beveled or pointed. As for the end 230.3, it advantageously has a pointed shape, a rounded shape or spherical cap.

The rear end 222.1 of the rod 222 advantageously comprises a slope oriented towards the bottom of the third electrode 206, intended to cooperate also with the end 230.3 of the radial finger 230 during a closing phase of the isolating switch.

The radial finger 230 advantageously serves anti-rotation means of the outer portion 208.1 relative to the inner portion 208.2. However, additional means can be provided.

We will now explain the operation of such a set of disconnectors.

On the Figure 6A the isolation switch can be seen in the closed position, the movable contact 208 ensures contact between the first electrode 202 and the second electrode 204, the radial finger 230 enters the radial passage 235 and ensures the axial attachment of the outer portion 208.1 and the inner part 208.2.

To open the isolating switch, an operator activates the displacement means 240, in the example shown, the worm moves the rod 18 axially rearward, driving the outer portion 208.1, the inner portion 208.2 is also moved axially via the radial finger 230. The axial displacement of the conductive member 208 can be carried out slowly, for example at a speed of the order of 0.02 m / s to 0.2m / s.

The movable contact 208 deviates from the first electrode 202, the displacement means 240 stop, the isolation disconnector is then in the open position, ie the first 202 and second 204 electrodes are no longer electrically connected and are remotely sectioning. In this position, none of the electrodes are grounded.

The disconnection distance is the minimum distance between the first 202 and second 204 electrodes necessary for the electrical insulation of the gas is sufficient to ensure the dielectric strength imposed by the standards applicable to this type of equipment.

During this first race, the spring 228 was compressed. When stopping the moving means 240, the spring 228 is kept compressed.

To return to the position in which none of the electrodes 202, 204 is grounded, it suffices to actuate the displacement means 240 in the opposite direction so that the connecting rod 218 moves forward.

To close the slow earthing switch, the operator again activates the moving means 240, the connecting rod 218 resumes its axial displacement towards the rear, as well as the outer 208.1 and inner 208.2 parts, until the outer portion 208.1 enters the third electrode 206 and contacts the periphery 206.2 of the central passage 206.1 of the ground electrode 206, as shown in FIG. Figure 7A . The second electrode 204 is then in electrical contact with the third electrode 206 (grounded) via the outer portion 208.1, the earthing switch of the second electrode 204 is closed. The spring 228 was again compressed. The maneuver can also be performed slowly, for example at a speed of the order of 0.02 m / s to 0.2m / s. The moving means 240 stop. Moving the inner part 208.2 therefore corresponds to the closing of a slow earthing switch.

To return to the position represented in Figure 7A it is sufficient to actuate the displacement means 240 in the opposite direction so that the connecting rod 218 moves forward.

To close the fast earthing switch, the operator again activates the moving means 240, the outer portion 208.1 and the inner portion 208.2 move backwardly solidly again. The axial finger 226 projecting from the bottom 206.3 of the electrode 206 then penetrates into the bore 236, comes into contact with the tip 230.3 of the radial finger 230 ( Figure 7B ), and pushes it radially outwards against the spring 232, as shown on the Figure 8B . This radial movement of the finger 230 causes the outer part 208.1 and the inner part 208.2 to separate.

Under the effect of the load of the spring 228, the inner portion 208.2 is pushed forward, while the outer portion 208.1 remains stationary. The inner portion 208.2 penetrates the central cavity of the first electrode 202. However, the outer portion 208.1 and the inner portion 208.2 remain in electrical contact, as can be seen in FIG. figure 8A .

The first electrode 202 is then electrically connected to the grounding electrode 206 via the inner portion 208.2 and the external part 208.1. The earthing switch of the first electrode 202 is then closed.

The forward movement of the inner portion 208.2, upon expansion of the spring 228, is rapid and thus the closure of the earthing switch of the first electrode 202 relative to the closing of the earthing switch the second electrode 204 is fast. The closing speed is of the order of 2 to 8 m / s, which ensures the closing performance on short circuit. The displacement of the inner portion 208.2 thus corresponds to the closing of a fast earthing switch.

Return to the position represented in Figure 7A , ie the openings of the earthing switches and the closing of the isolating switch is effected by an actuation of the displacement means 240 in a direction of movement of the rod 218 forward. The outer portion 208.1 then slides forwardly relative to the inner portion 208.2.

The outer portion 208.1 then deviates from the third electrode 206 of grounding, the electrodes 2 and 4 are no longer grounded: the earthing switches of the first 202 and second 204 electrodes are open. Then, the outer portion 208.1 comes into contact with the first electrode 202, the isolating switch is then closed.

The point 230.3 of the radial finger 30 then meets the end of the rod 222 and comes sliding on the slope, the finger 230 is then moved radially outwards against the spring 232. Then, when it is opposite the passage 235, the finger performs a radial displacement towards the X axis under the The effect of the spring 232. The outer portion 208.1 and the inner portion 208.2 are then again axially secured.

This sealed enclosure has a very low axial projection, since the size of the mechanical part of the disconnector protruding outside the sealed enclosure has been reduced. The spring can be arranged all or part in the enclosure due to its electrical insulation properties. It surrounds the rod 222 attached to the inner portion 208.2 of the movable contact 208 and securing it to the outer portion 208.1. The isolation and elastic energy storage functions are now geometrically superimposed by the present invention.

On the Figures 3A to 3G a second embodiment of a set of disconnectors according to the present invention, wherein the conductive element for electrically connecting the first and second electrodes is in one piece.

On the figure 3A the set of disconnectors according to the second embodiment can be seen in a state of closure of the isolating and opening isolating switch of the earthing switches.

The set of disconnectors comprises a first electrode 102 connected to the high or medium voltage line or to a cable outlet, a second electrode 104 connected to the circuit breaker, and a third electrode 106 of grounding, these three electrodes being aligned along the axis X.

The first 102 and the second 104 electrodes are disposed opposite one another at a distance of disconnection, the disconnection distance being, as written above, the minimum distance between the electrodes necessary for the electrical insulation of the gas is sufficient to ensure the dielectric strength imposed by the standards applicable to this type of material, the third electrode 106 is axially offset back of the second electrode 104.

In the example shown, the first X-axis electrode 102 has opposite the second electrode 104 a cavity 102.2 forming an electrical contact permitting the passage of the permanent current and an axial projection 102.3 in the cavity in the direction of the second electrode 104. forming an electrical contact made of a material allowing the establishment of an electric arc.

The second electrode 104 has an outer member 104.1 having a generally tubular shape partially closed at a first end 104.2 oriented towards the first electrode 102, by an annular wall 104.3 extending radially inwards toward the X axis , providing a central opening 104.4, an X axis sleeve 104.5 disposed inside the tube 104.1 connected to the tubular element 104.1 by an annular transverse wall 104.6 at a second end 104.5 opposite the first end 104.2.

On the Figures 4A to 4D it can be seen that the second electrode 104 is not made in one piece. On the one hand, the tubular element 104.1 and the annular wall 104.3 are made in one piece and that, on the other hand, the sleeve 104.5 and the annular transverse wall 104.6 are made in one piece. The assembly formed by the sleeve 104.5 and the transverse wall 104.6 are secured to one end of the tubular element 104.1 opposite the first electrode 102.

The third electrode 106 has a substantially tubular shape, which is for example connected to the metal casing in the case where the latter is connected to the ground, as is shown in FIGS. Figures 4A to 4B where the third electrode is mounted in the rear cover of the envelope and has the shape of a tulip.

The electrically conductive element 108 capable of being displaced along the axis X comprises an outer tube 110 of axial dimension sufficient to come into electrical contact with both the first electrode 102 and the second electrode 104 by an electrical contact 105. The tube 110 has an outer diameter substantially equal to the diameter of the cavity 102.2 of the first electrode 102 to allow it to slide inside the latter.

The conductive element also comprises an electrical contact 109 in the form of a tulip mounted at the inside of the conductive element 108 and intended to receive the axial projection 102.3.

The electrical contact 109 is fixed on a transverse wall 108.1 partially closing the inside of the tube of the conductive element.

The conductive element 108 comprises at a rear end 110.1 of the tube of the fastening means 112 in axial displacement of the tube 110 with a connecting rod 114.

The rod 114 is made in two parts, one of electrically conductive material and the other of insulating material and is in the form of a tube sliding in the sleeve 104.5 and connect to the conductive element 110 by the device 112.

The rod 114 comprises a front portion 114.1 in conductive material of larger diameter equal to the inner diameter of the sleeve 104.5 of the second electrode 104, which ensures electrical contact and axial guidance of the connecting rod 114. An electrical contact 118 is advantageously provided. at a rear end of the sleeve 104.5. The outer diameter of the larger diameter portion 114.1 is also substantially equal to the inside diameter of the third electrode 106, to allow a plugging of the portion 114.1 into the electrode 106 having an electrical contact adapted to the contact 104.1

The rod 114 also has a smaller diameter portion 114.2 made of insulating material with an outside diameter smaller than the inside diameter of the third electrode 106 for grounding. allow sliding without contact with the electrode 106.

The rod 114 also has a groove which allows it to be secured to the conductive element 108 by means of the device 112.

The set of disconnectors also comprises an elastic energy storage means 120 mounted in the second electrode 104 between the tube 104.1 and the sleeve 104.5. This elastic energy storage means 120 is, in the example shown, a helical spring mounted in reaction between the transverse wall 104.6 of the second electrode 104 and a rear end 108.1 of the conductive element 108.

On the figure 5 , we can see an enlarged view of the securing means 112 comprising a radial finger 122 mounted radially movable in a cage 124 secured to the outer tube 110 at its rear end 110.1, in a closing state of the disconnector.

The cage 124 has an axis orthogonal to the axis X.

The finger 122 is biased radially towards the X axis by a spring 126 mounted in a radial passage 128 formed in the tubular element 104.1 of the second electrode 104. The spring 126 is mounted in reaction between an annular bearing surface of the passage 128 and a head 130.1 of a pusher 130, the head 130.1 of the pusher 130 being in contact with the finger 122. The pusher 130 also comprises a radial abutment 130.2 limiting the radial displacement of the pusher 130 towards the axis X.

A spring 127 is also provided to bias the finger 122 away from the X axis mounted in reaction between a head 122.3 of the finger 122 and an annular bearing surface 124.1 of the cage 124.

The load of the spring 126 is greater than that of the spring 127 in order to permanently push the finger 122 towards the axis X.

The spring 127, mounted in the conductive element, makes it possible to maintain an equilibrium position of the finger 122 towards the outside against the spring 126.

The finger 122 is intended to cooperate by its radially inner end 122.1 with a groove 132 formed in the outer wall of the connecting rod 114. This groove 132 is provided so that it is opposite the passage 128 when the disconnector Isolation is closed. Thus, when the radially inner end 122.1 is in the groove 132, the conductive element 108 and the rod 114 are integral axially.

Advantageously, the ends 122.1, 122.2 of the radial finger 122 are rounded to facilitate sliding thereof on the different surfaces, as we shall see later.

The inner wall of the tube 104.1 also comprises a groove 134 behind the passage 128 made axially in front of the longitudinal end of the sleeve 104.5. This cavity 134 is intended to receive a radially outer end 122.2 of the finger 122.

The groove 134 advantageously comprises an axial end gently sloping on the side of the end 104.2 of the second electrode, so as to favor the exit of the end 122.2 of the finger 122 of the cavity towards the front, when it can move radially inward.

The front end 114.3 of the rod 114 is tapered forward so as to allow the finger 122 to go back on the connecting rod 114 at the end of the closing operation of the disconnector.

Anti-rotation means (not shown) are advantageously provided so that the finger 122 and the pusher 130 are permanently substantially in the same plane contained in the sheet plane.

Displacement means 136 are also provided for driving the conductive element 108 in translation along the axis X via the connecting rod 114. These displacement means are in the illustrated example of the lever type, but they can be of any other suitable type, for example rack or worm.

We will now explain the operation of the disconnect assembly according to the second embodiment.

In the position shown on the figure 3A the isolating switch is kept closed, ie the conductive element 108 is held in contact with the first 102 and the second 104 electrodes by the spring 120.

An operator wishing to open the isolating switch activates the displacement means which exerts an axial force on the connecting rod 114, the latter moves back along the axis X, driving the conductive element 108 rearwards by cooperation of the end 122.1 of the finger 122 secured axially to the conductive element 108 with the groove 132. The end 122.1 then slides on the inner surface of the tube 104.1 of the second electrode 104. The displacement of the conductive element 108 is effected against the spring 120, it is then compressed as indicated in figure 3B .

The contact between the conductive element 108 and the first electrode 102 is broken. The isolating switch is then open. The displacement means stop when the conductive element 108 abuts against the end of the sleeve 104.5 of the second electrode 104, such that the assembly is represented on the figure 3C . The finger 122, in particular its end 122.1, is aligned with the groove 134.

In this configuration, the isolating switch is open i.e. the first 102 and second 104 electrodes are no longer electrically connected and are remote sectioning. In this position, none of the electrodes are grounded.

The displacement as described can be carried out at a low speed of the order of 0.02 m / s to 0.2 m / s. To close the isolating switch, it suffices to perform the operations opposite to those described above.

To return to the position represented in figure 3A it is sufficient to actuate the displacement means 114 in the opposite direction so that the conductive element 108 moves forward.

To close the slow earthing switch of the second electrode 104, the operator activates the moving means again.

The rod still tends to drive the conductive element 108, but the latter being in abutment against the end of the sleeve 104.5, the forces exerted on the finger 122 through the slope formed in the groove 132 and that by the spring 127 tend to make out the end 122.1 of the finger 122 of the groove 132. The finger 122 then moves radially outwards, the end 122.2 then enters the groove 134. The conductive element 108 is then locked on the second electrode 104 in the position shown on the 3D figure . By cons, the rod 114 continues its sliding backwards so that its larger diameter portion 114.1 engages in the ground electrode 106 and comes into contact with it, as can be seen on the figure 3E and on the figure 4C . The moving means stop.

In this position, the earthing switch of the second electrode 104 is closed, in fact the second electrode 104 is grounded via the connecting rod 114.

The length of the larger diameter portion 114.1 is chosen so that the distance separating the rear end of the larger diameter portion coming into contact with the electrode 106 and the area behind the bevel at the front end the connecting rod is such that the portion of larger diameter 114.1 can be in contact with the electrode 106, while the end 122.1 of the finger is behind the bevel.

The displacement as described can be carried out at a low speed of the order of 0.02 m / s to 0.2 m / s. To open the earthing switch of the second electrode again and close the isolating switch, it is sufficient to perform the operations opposite to those described above.

To return to the position represented in figure 3A it is sufficient to actuate the displacement means 114 in the opposite direction so that the conducting element 114.1 moves forward.

To close the fast earthing switch of the first electrode 102, the operator activates the moving means again, the connecting rod makes a reduced stroke, for example of the order of a few mm, so that the the end 122.1 of the finger 122 meets the bevel, the finger then moves radially inwards, its opposite end 122.2 escapes the cavity 134 by sliding on the slope thereof, the conductive element 108 is then axially detached from the second electrode 104.

Under the action of the compressed spring 120, the conductive element 108 moves axially forward, the end 122.2 sliding along the inner face of the tube 104, for example with a high speed of the order of 2m / 8m / s and engages the first electrode 102. This is then grounded via the connecting rod 114, since the conductive element 108 is permanently in electrical contact with the second electrode 104 by the electrical contact 105 and since the second electrode 104 is itself grounded by the conductor 114.1. The earthing switch of the first electrode 102 is then closed, as can be seen on the Figures 3F and 4D .

The finger is then found to the right of the pusher 130.

The high speed with which the earthing switch of the first electrode closes, ensures the short-circuit closing performance of the disconnector.

To open the earthing switches and close the isolating switch, the operator activates the moving means in the opposite direction in order to move the connecting rod 114 forward, the latter, in particular its part of more large diameter 114.1, away from the electrode 106, the two earthing switches open and the isolating switch closes simultaneously ( figure 3G ).

The rod 114 continues its stroke, the end 122.1 slides on the beveled front end of the connecting rod 114 and moves radially outwardly.

The connecting rod 114 moves forward until the groove 132 is at right finger 122 and its end 122.1 falls into the recess 132. The conductive element 108 and the connecting rod 114 are then back together. axially as represented on the Figures 3A and 4A .

This maneuver is generally performed slowly, of the order of 0.02 m / s to 0.2 m / s.

In both embodiments, only one axial immobilization means is described, but it is understood that several may be provided, advantageously distributed angularly in a regular manner and advantageously in the same transverse plane.

In the case of the second embodiment, the presence of several fingers 122 makes it possible to improve the axial guiding of the conductive element 108 in the electrode 104 and to reduce the force per finger.

In the second embodiment, the spring 120 is disposed inside the second electrode 104 as is particularly visible on the Figure 4A , which makes it possible to reduce the outgrowth towards the outside of the enclosure, formed by the fast MALT mechanism with respect to the first embodiment. The passage of the current in the turns of the spring can be avoided by placing an electrical insulating plate of a few millimeters at one of its ends.

Claims (18)

An assembly of disconnectors for metal-enclosed medium and high voltage distribution station having a first electrode (2, 102, 202), a second electrode (4, 104, 204) and a third grounding electrode (6, 106, 206) disposed in this order along a longitudinal axis (X), a movable member (8, 108, 208) movable along said longitudinal axis (X), said movable member (8, 108, 208). having a first longitudinal end for contacting the first (2, 102, 202) and the second (4, 104, 204) electrode, a second longitudinal end for engaging axial displacement means
characterized in that the movable member (8, 108, 208) comprises a first electrically conductive portion (8.1, 114, 208.1) and a second portion (8.2, 110, 208.2), axially secured in a first direction to provide the earth the second electrode (4, 104, 204) and able to disengage axially, the second part (8.2, 110, 208.2) being able to move in a second direction, while remaining electrically connected to the first part (8.1, 114, 208.1), to permit closing of the earthing switch of the first electrode (2, 102, 202). An isolator assembly as claimed in claim 1, wherein the displacement of the movable member (8, 108, 208) in the first direction is obtained by activation of the displacement means and the displacement of the second part (8.2, 110, 208.2) of the movable element in the second direction is obtained by the release of an elastic means (28, 120, 228) compressed during the moving in the first direction. Set of disconnectors according to claim 1 or 2, comprising means (20, 112, 220) for securing the first and second parts of the movable element (8, 108, 208), the annihilation of the securing obtained by the means for securing (20, 112, 220) and the release of the load of the elastic means (28, 120, 228) thus compressed is automatically obtained by a further relative displacement in the first direction of at least a portion of the movable member (8, 108, 208). Assembly according to one of claims 1 to 3, wherein the first portion (114) of the movable element is in direct contact with the displacement means and is partially electrically conductive material coming into electrical contact with the third electrode (106). ) to ground the first and second electrodes (104). An isolator assembly as claimed in claim 4, wherein the first portion (114) has a larger diameter portion (114.1) of electrically conductive material and a smaller diameter insulating portion (114.2), the contact with the third electrode (106) being obtained by contact between the larger diameter portion (114.1) and the third electrode (106). An isolator assembly as claimed in claim 5 in combination with claim 2, wherein the resilient means (120) is mounted in reaction between a radial wall (104.6) of the second electrode (104), and an axial end (108.1) of the second portion (110) interposed between said radial wall (104.6) of the second electrode (104) and the first electrode (102), the second electrode (104) having a radially outer tube (104.1) and a radially inner tube (104.5) connected by said radial wall (104.6), the elastic means (120) being arranged between the two tubes concentrically. Set of disconnectors according to one of claims 5 to 6 in combination with claim 3, wherein the securing means (112) comprise a finger (122) mounted radially movable in a cage secured to the tube of the second portion (110). , the connection between the second portion (110) and the first portion (114) being obtained by cooperation of a radially inner end (122.1) of the finger (122) with a groove (132) formed in the outer face of the tube of the first portion (114), said finger being elastically biased towards the longitudinal axis (X) by an elastic means (126) mounted radially in the outer tube (104.1) via a pusher, and wherein the radially outer tube (104.1) of the second electrode (104) comprises on an inner face a groove (134), said groove (134) for securing the second portion (110) to the spring cage by penetration of a radially end outside the finger (122) in said groove (134) and by engaging the other radially inner end (122.1) of the finger (122) with the outer surface of the first portion (114) separate from the groove (134), the finger being biased radially away from the axis (X) by an elastic means mounted in the cage, the load of the second elastic means being less than that of the first elastic means. An isolator assembly as claimed in claim 7, wherein the first portion (114) has at one end (114.3) upstream in the first direction a slope facing the first electrode (102), the release of the load of the elastic means (120). ) effected by sliding of the radially inner end (122.1) of the finger (122) on said slope, by a radial displacement of the finger (122) inwardly and an exit of the radially outer end (122.2) finger (122) groove (134), the second part then being detached from the second electrode (104). Disconnect assembly according to one of claims 1 to 3, wherein the first part (8.1, 208.1) has an end intended to come into electrical contact with the first (2, 202). and the second electrode (4, 204) and a second longitudinal end engaged with the displacement means, and the second portion (8.2, 208.2) has a first longitudinal end intended to come into electrical contact with the first (2, 202). and the second electrode (4, 204), and wherein the first portion (8.1, 208.1) is radially outer and surrounds the radially inner second portion (8.2, 208.2), the second end of the first portion (8.1, 208.1) being of electrically insulating material and said second part (8.2, 208.2) being able to be secured axially to the first part (8.1, 208.1) by securing means (20, 220), said second part (8.2, 208.2) having one end electrically conductive on the side of the first electrode (2, 202) and an electrically insulative end on the side of the third electrode (6, 206). Set of disconnectors according to one of claims 1 to 3 and 9 in combination with claim 2, wherein the elastic means (228) is of electrically insulating material and is disposed at least partly in the sealed casing (201) in bearing against the sealed envelope and the movable contact (208). Disconnector assembly according to claim 10 in combination with claim 3, wherein the securing means are arranged outside the sealed envelope (201) in a cylindrical shell (242) open at one end and bordering the central passage (206.1) of the grounding electrode (206). Set of disconnectors according to claim 11, wherein the securing means (220) comprise a finger (230) movable radially and an elastic return means (232) towards the longitudinal axis (X), said radial finger (230) being resiliently biased towards the longitudinal axis (X), said radial finger (230) being mounted on the first portion (208.1) and the second portion (208.2) radially inner having a radial passage (235) for receiving the radial finger (230) the cylindrical casing (242) being provided with a bottom from which a central finger (226) projects along the longitudinal axis (X) adapted to urge the radial finger (230) through a bore (236). ) practiced in the second part (208.2) and in which opens said passage (235) to escape said passage. Set of disconnectors according to claim 9 in combination with claim 3, wherein the securing means (20) comprise a finger (30) movable radially and an elastic return means (32) mounted in reaction in a cage (34) between one end of the cage (34) and the radial finger (30), said radial finger (30) being resiliently biased towards the longitudinal axis (X), said radial finger (30) being mounted on the first portion (8.1) and the second portion (8.2) radially inner having a passage (35) radial to receive the radial finger (30), and wherein the third electrode (6) has at a downstream end in the second direction a bottom ( 6.3) from which protrudes a finger (26) central on the longitudinal axis adapted to urge the radial finger (30) by penetration into a bore (36) formed in the second part (8.2) and into which said passage (35) opens. ) to make it escape from said passage. Set of disconnectors according to one of claims 9 and 13 wherein the third electrode (6) comprises axial guide means (24) of the first (8.1) and second (8.2) parts of the movable element, also forming a support for the elastic means (28), the guiding means (24) comprising for example a tube integral with the bottom (6.3) and coming to be interposed radially between the first portion (8.1) and the second portion (8.2) radially inner, said tube having an axial lumen (37) receiving the radial finger (30). Disconnector assembly according to claim 12 or 14, wherein the radially inner second portion (8.2, 208.2) has at one longitudinal end (22.1, 222.1) downstream of the passage in the first direction a slope oriented away from the passage (35, 235) intended to cooperate with the tip of the radial finger (30, 230) to allow the radial finger (30, 230) to slide radially outwardly and into the passage (35, 235) for securing the first (8.1, 208.1) and the second (8.2, 208.2) portion of the conductive element. Disconnect assembly according to any one of claims 1 to 15, wherein the moving speed of the movable element in the first direction is between 0.02 m / s and 0.2 m / s. Medium and high voltage metal encased substation, comprising a set of disconnectors according to any one of the preceding claims, wherein the metal casing is connected to earth and the third electrode (6, 106, 206) and connected to the metal envelope, the first electrode (2, 102, 202) being for example connected to a high or medium voltage line or a cable outlet, the second electrode (4, 104, 204) being connected for example to a circuit breaker. A method of severing and grounding a medium and high voltage substation, said substation comprising a first electrode, a second electrode and a third grounding electrode, arranged in this order along a longitudinal axis a movable member movable along said longitudinal axis, said movable member having a first longitudinal end for contacting the first and second electrodes, a second longitudinal end; adapted to engage axial displacement means, said method comprising the steps of: a) moving the movable element in a first direction to interrupt the electrical connection between the first and the second electrode, b) moving the movable member of an additional stroke in the first direction to electrically connect the second and the third electrode, c) moving at least a portion of the movable member further in the first direction to release at least the second portion of the movable member and move in the second direction and electrically connects the first and third electrode.

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