EP1091378A1 - Self-blast circuit breaker with pressure relief valve and filling valve - Google Patents

Abstract

The circuit breaker has a first assembly with a fixed contact having a fixed contact and an arc contact. A second assembly has a principle contact and moving arc contact with a breathing tube. The compression chamber (42) has a movable piston (60) opposed in motion to a valve (40) by the admission of gas from the compression chamber. A second valve (62) closes the entrance during the circuit breaking phase when the compression chamber pressure exceeds a predetermined level during the valve closed state.

Description

• un premier sous-ensemble contact fixe comprenant un contact principal fixe et un contact d'arc fixe,
• un deuxième sous-ensemble contact mobile comportant un contact principal mobile, et un contact d'arc mobile associé à une buse de soufflage,
• une chambre d'expansion ayant un premier cylindre en communication avec la buse de soufflage par un canal de guidage de l'écoulement gazeux,
• une chambre de compression ayant un deuxième cylindre solidaire du sous-ensemble contact mobile pour le pistonnage du gaz au cours de la phase d'ouverture du disjoncteur,
• et un clapet susceptible d'être dans un état fermé ou un état ouvert en fonction de la pression différentielle du gaz entre la chambre d'expansion et la chambre de compression.

The invention relates to a self-expanding circuit breaker housed in an insulating envelope filled with insulating gas with high dielectric strength, and containing:

• a first fixed contact sub-assembly comprising a fixed main contact and a fixed arcing contact,
• a second movable contact sub-assembly comprising a movable main contact, and a movable arcing contact associated with a blowing nozzle,
• an expansion chamber having a first cylinder in communication with the blowing nozzle by a channel for guiding the gas flow,
• a compression chamber having a second cylinder secured to the movable contact sub-assembly for the pistoning of the gas during the opening phase of the circuit breaker,
• and a valve capable of being in a closed state or an open state as a function of the differential pressure of the gas between the expansion chamber and the compression chamber.

A known circuit breaker of the kind mentioned is described in document DE 3915700. The support element of the first fixed contact sub-assembly is formed by a socket cylindrical, having the same diameter as the main tulip fixed contact. The compression chamber for the gas piston includes a full piston, on which slides the movable cylinder.

The object of the invention is to provide a self-expanding circuit breaker having high shutdown performance, and regulated distribution of gas pressure blowing.

The autoexpansion circuit breaker is characterized in that the compression comprises a semi-fixed piston arranged opposite the valve for the admission of gas into the compression chamber during the phase and a valve serving as a safety valve during the shutdown, when the pressure inside the compression chamber exceeds one predetermined threshold in the closed state of the valve.

According to a preferred embodiment, the valve is housed in a space annular piston, and is biased in the closed position by a spring reminder. The valve is mounted with limited sliding on a fixed shaped socket tubular coaxially surrounding an actuating rod of the contact sub-assembly mobile.

According to a characteristic of the invention, the socket is equipped with first means stop delimiting the valve displacement travel between the closed state and open state. The displacement of the semi-fixed piston is limited by second stop means provided on the socket.

According to another characteristic of the invention, the semi-fixed piston comprises a friction drive segment, intended to ensure the relative movement of the piston in relation to the valve for the admission of gas into the compression during the closing movement of the circuit breaker.

• la figure 1 est une vue en coupe axiale du disjoncteur à autoexpansion selon l'invention, l'appareil étant en position de fermeture ;
• la figure 2 montre une vue partielle de la figure 1 illustrant le disjoncteur en position d'ouverture ;
• la figure 3 est une vue partielle à échelle agrandie de la figure 1 représentant la chambre de compression avec le clapet et la soupape dans l'état fermé ;
• la figure 4 est une vue identique de la figure 3 lorsque la soupape se trouve en position de régulation de surpression suite à la coupure de courants de fortes intensités ;
• la figure 5 est une vue identique de la figure 3 lors la soupape se trouve en position de remplissage à l'enclenchement du disjoncteur ;
• la figure 6 est une vue identique de la figure 2 lors d'une phase de coupure par pistonnage de courants de faibles intensités ;
• la figure 7 est une vue identique de la figure 2 lors d'une phase de coupure par expansion de courants de fortes intensités ;
• la figure 8 montre une demi-vue en coupe d'un disjoncteur selon une variante de réalisation.

Other advantages and characteristics will emerge more clearly from the description which follows of an embodiment of the invention, given by way of nonlimiting example and represented in the appended drawings in which:

• Figure 1 is an axial sectional view of the autoexpansion circuit breaker according to the invention, the device being in the closed position;
• Figure 2 shows a partial view of Figure 1 illustrating the circuit breaker in the open position;
• Figure 3 is a partial view on an enlarged scale of Figure 1 showing the compression chamber with the valve and the valve in the closed state;
• FIG. 4 is an identical view to FIG. 3 when the valve is in the overpressure regulation position following the interruption of high current currents;
• Figure 5 is an identical view to Figure 3 when the valve is in the filling position when the circuit breaker is engaged;
• FIG. 6 is an identical view to FIG. 2 during a phase of breaking by piston of low intensity currents;
• FIG. 7 is an identical view to FIG. 2 during a cut-off phase by expansion of high intensity currents;
• Figure 8 shows a half-sectional view of a circuit breaker according to an alternative embodiment.

With reference to FIGS. 1 and 2, a circuit breaker 10 with autoexpansion comprises a insulating jacket 12 filled with insulating gas with high dielectric strength, in particular sulfur hexafluoride SF6, a first contact sub-assembly fixed CF and a second mobile contact subset CM. Envelope 12 contains a switching chamber 14 with arc blowing nozzle 16, a device of main contacts 18, 20 for the passage of permanent current, and a device of arcing contacts 22, 24 to define the cut-off interval 26 during opening circuit breaker 10.

The movable arcing contact 24 is shaped as a tulip contact, subject to a rod 28 tubular, which is mechanically connected to a control mechanism (not shown) authorizing the axial sliding of the mobile assembly constituting the second mobile contact CM sub-assembly. The envelope 12 is carried by a fixed base 30 crossed by rod 28, and serving as a support for the entire pole. The movable arcing contact 24 is separated from the expansion chamber 32 by a annular insulating wall 34, which is coaxially surrounded by the nozzle 16 of blowing by forming a channel 36 in communication with the cutoff interval 26 following the separation of the arcing contacts 22, 24.

The expansion chamber 32 is delimited at the bottom by a bottom 38 which has a valve 40 for communication with a compression chamber 42 for blowing the blowing gas. The valve 40 is pressure controlled relative of the gas contained in the expansion chamber 32, and the compression 42.

The movable main contact 20 is formed by a conductive cylindrical ring, fixed at the base of the nozzle 16 to confine the expansion chamber 32 with a first cylinder 44.

The fixed main contact 18 is constituted by a tulip contact surrounding coaxially the fixed arcing contact 22. In the circuit-breaker latching position, the movable main contact 20 is in engagement with the fixed main contact 18, and allows the passage of permanent current. The first fixed contact subset CF is carried by a support element 46 made of aluminum.

The operation of such a circuit breaker 10 when the arcing contacts 22, 24 are opened conventional, and depends on the intensity of the short circuit in the cutoff interval 26.

For strong currents, the valve 40 is in the closed state, because the gas pressure in the expansion chamber 32 due to the heating of the arc, is greater than the gas pressure in the compression chamber 42. At zero crossing of the current, the gas stored in the expansion chamber 32, is sent to the interval cutout 26 for blowing the arc.

For low currents, the valve 40 is in the open state because the expansion of the gas due to overheating by the arc, is insufficient. The gas pressure in the chamber expansion 32 is less than the pressure of the compressed gas in the compression 42 by plunging. The cold compressed gas is then pushed towards the expansion chamber 32 through the valve 40, and then mixes with the gas hot stored in the expansion chamber 32. The mixture is sent to the cutoff interval 26 for blowing the arc at the zero crossing of the current.

According to the invention and with reference to Figures 3 to 5, the bottom 38 of the chamber expansion 32 is secured to the movable rod 28 and to the first cylinder 44, and has a hole 50 at the seat of the valve 40. A deflector 52 is arranged in the expansion chamber 32, being subject to the bottom 38 by a screw 54. In in the closed state, the valve 40 bears on the seat of the bottom 38 by closing the hole 50. The deflector 52 has a radial protuberance serving as an end stop. stroke of the valve 40 when the latter is stressed in the open state. The presence of the radial protuberance also constitutes a baffle for protecting the valve 40.

The compression chamber 42 is confined by a second cylinder 56 fixed to the bottom 38 and at the end of the first cylinder 44 by surrounding the tubular rod 28. The second cylinder 56 of conductive material, part of the contact sub-assembly mobile CM, and cooperates with a sliding contact 58 for the passage of current. The second cylinder 56 slides with sealing on a semi-fixed piston 60, which is arranged coaxially opposite the bottom 38, cooperating with a valve 62 biased in the closed position by a spring 64 (Figure 3). In this position, the valve 62 closes the annular space of the piston 60, and prevents communication of the compression chamber 42 with the internal volume of the envelope 12.

The valve 62 can slide axially along a fixed sleeve 65 towards a open position (figure 4) as soon as the pressure inside the pressure chamber compression 42 reaches a predetermined threshold in the closed state of the valve 40. The socket 65 is equipped with first stop means 70 defining the travel of movement of the valve (62) between the closed state and the open state. The socket 65 is provided with second stop means 72 for delimiting the two positions extremes of semi-fixed piston 60.

The semi-fixed piston 60 has a guide segment 66 and a segment 68 both having annular shapes corresponding to the internal diameter of the second cylinder 56. When the circuit breaker is engaged 10, the displacement of the rod 28 in the closing direction (arrow F1, FIG. 5) simultaneously causes the piston 60 to be driven by the friction effect of the cylinder 56 on segment 68, and by the pressure difference between the compression 42 and the internal volume of the enclosure 12 to allow the admission of SF6 gas in the compression chamber 42. The guide segment 66 is arranged between the segment 68 and the compression chamber 42. The drive segment 68 and / or the guide segment 66 also provide if necessary, a partial sealing function.

In FIG. 6 illustrating the separation of the arcing contacts 22, 24 in the case of low intensity currents, the valve 62 of the compression chamber 42 is is in the closed position, and the valve 40 is moved into the open state by the differential pressure. The gas flow for extinguishing the arc in the meantime cutoff 26 comes mainly from the piston of the gas in the compression 42.

Figure 7 shows the cut of high currents, with the filling of the expansion chamber 32 by hot gases following the heating of the arc. The valve 40 is closed, as is valve 62. The pressure in the compression 42 is regulated during the opening stroke by means of the valve 62, which opens as soon as the authorized threshold is exceeded (Figure 4).

After the arc has been extinguished, the circuit breaker 10 can be actuated by the control to the switch-on position. The relative displacement of the piston 60 by compared to valve 62 for the admission of gas into the compression chamber 42, is derived from the closing movement of the rod 28, which drives the sub-assembly mobile contact CM, the second cylinder 56, and the segment 68.

In the variant embodiment of FIG. 8, the piston 60 is floating inside the second cylinder 56, and the valve 62 is formed by a simple valve urged into closed position by one or more compression springs 64. A segment unique provides friction drive and partial sealing.

In the previous embodiments, the circuit breaker was housed in a insulating jacket intended to ensure the dielectric behavior in the open air. Alternatively the same circuit breaker can be housed in an enclosure itself contained in an enclosure filled with a gas of high dielectric strength, for an armored installation.

Claims (8)

Self-expanding circuit breaker isolated by an insulating gas with high dielectric strength, and comprising: a first fixed contact sub-assembly (CF) comprising a fixed main contact (18) and a fixed arcing contact (22), a second movable contact sub-assembly (CM) comprising a movable main contact (20), and a movable arcing contact (24) associated with a blowing nozzle (16), an expansion chamber (32) having a first cylinder (44) in communication with the blowing nozzle (16) by a channel (36) for guiding the gas flow, a compression chamber (42) having a second cylinder (56) integral with the movable contact sub-assembly (CM) for the pistoning of the gas during the opening phase of the circuit breaker (10), and a valve (40) capable of being in a closed state or an open state as a function of the differential pressure of the gas between the expansion chamber (32) and the compression chamber (42), characterized in that the compression chamber (42) comprises a semi-fixed piston (60) arranged opposite the valve (40) for the admission of gas into the compression chamber (42) during the phase of engagement, and a valve (62) serving as a safety valve during the shutdown phase, when the pressure inside the compression chamber (42) exceeds a predetermined threshold in the closed state of the valve (40). Self-expanding circuit breaker according to claim 1, characterized in that the valve (62) is housed in an annular space of the piston (60), and is biased in the closed position by at least one return spring (64). Self-expanding circuit breaker according to claim 2, characterized in that the valve (62) is slidably mounted on a fixed sleeve (65) of tubular shape coaxially surrounding a rod (28) for actuating the subassembly mobile contact (CM). Self-expanding circuit breaker according to claim 3, characterized in that the socket (65) is equipped with first stop means (70) delimiting the stroke movement of the valve (62) between the closed state and the open state. Self-expanding circuit breaker according to claim 3 or 4, characterized in that the sleeve (65) is equipped with second stop means (72) cooperating with the semi-fixed piston (60). Self-expanding circuit breaker according to claim 1, characterized in that the semi-fixed piston (60) has a friction drive segment (68), for ensuring the relative movement of the piston (60) relative to the valve (62) for the admission of gas into the compression chamber (42) during the closing movement of the circuit breaker (10). Self-expanding circuit breaker according to claim 6, characterized in that the second cylinder (56) slides on the piston (60), which is provided with a guide segment (66) arranged between the segment (68) and the compression (42). Self-expanding circuit breaker according to claim 6, characterized in that the piston (60) is mounted floating inside the second cylinder (56).

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