EP0680063B1 - Medium voltage electric switch - Google Patents

Description

The present invention relates to a switch intended to be used as a circuit breaker as well than a medium voltage electric switch.

We know a switch-disconnector as described in document US 5 168 139 which comprises on the one hand, a vacuum switch tube mainly comprising a housing insulating tubular closed by two caps of conductive ends crossed by two axes of coaxially opposite contacts having front contact faces, and on the other hand, two breaking contacts, of the leaf type, one of the breaking contacts being mounted in parallel with the vacuum switch tube, while the other cut-off contact is mounted in series with the parallel circuit thus formed. In operation, when the switch is closed, and the two cut-off contacts in a stable closed position, the vacuum switch is kept open during operation of the switch. When opening the switch-disconnector, the contacts of the vacuum switch are first closed, then the parallel-mounted breaking contact is open, then the switch contact at vacuum is opened, and finally the second contact arranged in series is open.

However, this device requires two separate switch control systems, hence it results in that its size is particularly large.

We also know a multi-pole rotary switch as described in the document FR2,668,851 (closest state of the art), and which consists mainly of a sealed revolution envelope, filled with a gas with high dielectric strength, the inner periphery of which carries, by pole, a fixed input contact, a fixed output contact and a fixed earthing contact. These contacts are angularly spaced and cooperate with a contact-shaped bridge swivel knife carried by a rotary control shaft extending in the axis of the envelope. In this realization which does not use the technique of vacuum cutting, the aforementioned tree can selectively occupy three positions, namely, a position opening, closing position, and grounding position.

The present invention solves the problem of creating a switch and a circuit breaker using the vacuum breaking technique which is simple in design and reduced dimensions.

To this end, the present invention relates to a medium voltage electric switch comprising a sealed enclosure filled with a dielectric gas in which are housed a first fixed contact electrically connected to a first connection terminal, a second fixed contact electrically connected to a second connection terminal, a conductive bridge mobile with first and second mobile contacts intended to cooperate respectively with the first and second fixed contacts and a control mechanism coupled to said bridge to establish or interrupt the electrical circuit between the first and second terminals of connection, this switch being characterized in that it further comprises a bulb unladen containing a third fixed contact electrically connected to one, called the second, of the two connection terminals, and a third movable contact electrically connected to said bridge at an intermediate point located between the first and second movable contact and mechanically coupled to said control mechanism and sequencing means intended to establish the opening and closing sequences of the first, second and third movable contacts associated with the first, second and third fixed contacts cooperating with the aforementioned control means, so that in the open or closed stable position of the switch, the third fixed and movable contacts are separated, and that during opening or closing operations of the switch, the third fixed contacts and mobile momentarily close to switch the arc associated with the first fixed contacts and mobile or to the second fixed and mobile contacts.

According to a particular embodiment, said bridge is rotary.

According to a particular characteristic, this bridge comprises two distinct opposite arms, a first arm, one of the ends of which has said first movable contact and of which the other end is pivotally mounted around an axis, and a second arm, one of the ends is provided with said second movable contact and the other end of which is mounted pivoting around said axis.

According to another particular characteristic, the aforementioned control mechanism comprises a crank linked in rotation to a driving shaft, and a first and a second connecting rod, coupled by one of their ends to the crank and by their other end, first and second arms respectively.

Advantageously, the first aforementioned terminal is an input range and the second terminal above is an output range.

According to another characteristic, the aforementioned sequencing means are adapted so to keep the third fixed and movable contacts separated in a stable position from the switch, and to close these two contacts during the opening of the switch, prior to the separation of the second fixed and mobile contacts, and, during closing of the switch, after closing of the second fixed and movable contacts.

According to another characteristic, said aforementioned sequencing means include a range fixed extended provided on the aforementioned first fixed contact, remaining in contact with said first movable contact over a predetermined stroke of said first movable contact, and a restricted fixed range provided on the second fixed contact not remaining in contact with said second movable contact over a predetermined stroke of the latter, during its displacement.

According to another characteristic, the third movable contact is carried by a movable rod in translation which is requested by spring means in the direction of opening of the third fixed and movable contacts, said rod cooperating with means provided on the arms above defining the sequencing of the opening and closing of the third aforementioned fixed and mobile contacts.

According to a particular embodiment, the aforementioned means comprise at least one cam secured to the first or second arm, the profile of which defines the above-mentioned sequencing.

According to an alternative embodiment, the aforementioned means comprise a light provided in one of the arms cooperating with a lug secured to a connecting rod so connected articulated by one of its ends, to the aforementioned rod, and by its other end, to a crank mounted free to rotate on the aforementioned axis.

According to a particular characteristic, the aforementioned light is of arcuate shape and comprises a step so as to form two portions of light of different widths.

According to another alternative embodiment, the switch further comprises a fourth fixed contact which is connected to earth, which is diametrically opposite to the second fixed contact relative to said axis and a fifth fixed contact electrically connected to said second terminal which is diametrically opposite the first fixed contact with respect to said axis, said fourth and fifth fixed contacts cooperating with the first and second respectively movable contact in switch earth position.

But other advantages and characteristics of the invention will appear better in the description which follows and refers to the appended drawings given solely by way of example non-limiting and in which:

Figures 1 to 7 illustrate views in radial section of a circuit breaker according to a particular embodiment of the invention, in different positions corresponding to different circuit breaker opening and closing stages.

Figure 1 illustrates the circuit breaker in the closed position.

Figure 2 illustrates the circuit breaker being opened, in the arc switching position associated with the second fixed and mobile contacts.

Figure 3 illustrates the circuit breaker being opened, at a more advanced stage than the previous.

Figure 4 illustrates the circuit breaker in the fully open position.

Figure 5 illustrates the circuit breaker being closed.

Figure 6 illustrates the circuit breaker being closed, at a more advanced stage than the previous.

FIG. 7 illustrates the circuit breaker being closed, in the switching position of the arc associated with the first fixed and mobile contacts.

FIG. 8 illustrates an operating diagram representing the state of opening or closing of the various contacts of the circuit breaker, namely, the first fixed contacts and mobile, the second fixed and mobile contacts, as well as the vacuum bulb contacts, function of the different stages of opening and closing of the circuit breaker.

FIGS. 9 to 11 illustrate views in radial section of a switch conforming to a another embodiment of the invention respectively for a closed position, for a position open, and a switch ground position.

Figures 12-14 show similar views of the same switch in different positions corresponding to different closing stages.

Figure 15 illustrates an operating diagram similar to that of Figure 8, but representing the state of the various switch contacts.

Figures 16 to 20 illustrate views in radial section of a switch according to a another embodiment of the invention for different positions of the corresponding switch respectively to a closed position, to an opening start position, a position of end of opening, an open position and a grounding position.

Figures 21 to 21c respectively illustrate, in schematic views, different stages of opening a circuit breaker according to another embodiment of the invention in which the driver bridge is monobloc.

In Figures 1 to 7, we see a switch according to the invention used as a medium voltage circuit breaker D and housed in a sealed enclosure E filled with a gas dielectric whose insulating wall can be that of a pole or of the three poles of circuit breaker D. It will be noted that the wall of the enclosure may, according to another embodiment, be metallic. The pole shown in the figures has two sealed crossings 22, 23, current input and output conductor respectively, supporting a fixed contact input 1 and a fixed output contact 2 which terminate outside enclosure E by connection terminals A, B respectively constituting an input range and a range of exit.

The circuit breaker D also comprises on the one hand, a movable conductive bridge P and a control mechanism M cooperating to establish or interrupt the current between the first and second connection terminals A, B, as well as a bulb 5 comprising two respectively fixed 6 and movable 7 contacts, respectively connected to the fixed contact of output 2 and at the aforementioned bridge P to switch the arc associated with the first or second fixed and mobile contacts as will be explained later.

The aforementioned movable conductive bridge P comprises two arms 8, 9 connected in an articulated manner by one of their ends, to an axis X integral with the enclosure E, and the ends of which free form a first and a second movable contact 3, 4 intended to come into contact respectively with the aforementioned first and second fixed contacts 1, 2 by rotation of the arms 8, 9 around the aforementioned X axis. This rotation of the arms 8, 9 is controlled by the mechanism control M which is mainly constituted by a crank 10 linked in rotation with a drive shaft 24 extending parallel to the aforementioned axis X and by two connecting rods 11, 12 articulated by one of their ends to an axis 25 integral with the aforementioned crank 10, and by their opposite ends, around two axes 26, 27 distinct and integral respectively of the two aforementioned arms 8, 9.

The vacuum interrupter 5 is constituted by a cylindrical wall 5a, for example shaped with the wall of the enclosure E and comprising a housing 5b receiving the two contacts fixed and mobile respectively 6, 7 of the bulb 5. The fixed contact 6 is connected by an element conductor 6a at the aforementioned second fixed contact 2, while the movable contact 7 of the bulb 5, said third movable contact, is fixed to one 13a of the ends of a rod 13 mounted sliding through an intermediate wall 5c of the bulb 5, and so connected articulated by its opposite end 13b, to one 18a of the ends of a connecting rod 18 connected articulated by its other end 18b, to a second crank 19 mounted freely rotating around the aforementioned central fixed axis X. The third fixed contacts and mobile 6, 7 of the vacuum interrupter 5 are permanently recalled to the open position by a spring 14, interposed between the intermediate wall 5c and the bottom wall 5d of the bulb 5, a sealing bellows being interposed between the third movable contact 7 and the wall intermediate 5c.

The circuit breaker D of the invention also includes suitable sequencing means to establish the opening, closing sequences of the first, second and third movable contacts 3, 4, 7, associated with the first, second and third aforementioned fixed contacts 1, 2, 6. These means comprise an extended fixed range formed on the first fixed contact 1, a restricted fixed area 2a formed on the second fixed contact 2, as well as a light 16, arched, consisting of two light portions 16b, 16c of different widths connected by forming a step 16f, said light 16 cooperating with a lug 17 fixed to the aforementioned link 18 perpendicular to its axis.

In FIGS. 9 to 14, we see a switch I constituted in the same way as the circuit breaker D previously described, but further comprising a fourth fixed contact 20 connected to earth T, and a fifth fixed contact 21 electrically connected to the second contact aforementioned fixed 2.

Figures 16 to 20 also show a switch I including a fourth contact fixed earth 20, and a fifth fixed contact 21 electrically connected to the second fixed contact 2, which differs from the switch I previously described, by the structure means establishing the opening and closing sequences of the third contacts fixed and mobile 6, 7 of the vacuum interrupter 5.

According to this alternative embodiment of the invention, the second arm 29 comprises a cam 15 intended to cooperate directly with the rod 13 to close or open the third fixed and mobile contacts 6.7.

In FIGS. 21 to 21c, an embodiment of a circuit breaker D is seen in which a bridge monobloc and rotating conductor is used to authorize or interrupt the passage of the current between a first fixed contact 1 having an extended fixed range 1a, and a second fixed contact 2 having a restricted fixed range 2a. This bridge 8 is rotated by a control shaft not shown and is electrically connected to the movable contact 7 of a vacuum interrupter S whose fixed contact 6 is electrically connected to the second fixed contact above 2.

The operation of the circuit breaker described in Figures 1 to 7 will be explained in what follows with reference to Figures 1 to 8.

In FIG. 1, the circuit breaker D is in the closed position, the contacts between the first fixed and mobile contacts 1, 3 and the second fixed and mobile contacts 2, 4 are closed, thus allowing the passage of current between the input and output terminals A, B, and the contacts 6,7 of the vacuum interrupter are open. In FIG. 2, the crank 10 has been rotated by the control shaft 24, by an angle of about 30 degrees (according to arrow F), which caused the angular displacement of the two arms 8, 9 of the bridge conductor P of a corresponding angle. During this movement, the edge forming recess 16f of the light 16 formed in the second arm 9 is in contact with the lug 17 integral with the link 8, which causes the rotation of the link 18 around the central axis X via the second crank 19, and causes the translation of the rod 13 towards the top of the bulb 5 so as to close the third fixed and mobile contacts 6, 7.

In this position of the conductive bridge P, the first fixed and mobile contacts 1, 3 are still closed, due to the extent of the contact range 1a of the first fixed contact 1 in L-shaped, while the second fixed and movable contacts 2,4 opened after closing of the contacts 6,7 of the bulb, which resulted in the switching of the arc on the vacuum interrupter 5.

In FIG. 3, it can be seen that after an additional rotation of the control shaft 24, having caused a corresponding rotation of the two arms 8, 9, the third fixed contacts and mobile 6, 7 of the vacuum interrupter 5, open and cut off the electric current between terminals A and B. After the opening of the third fixed and mobile contacts 6, 7 and interruption of the current, the first fixed and mobile contacts 1, 3 open, which are fully open in Figure 4, showing the circuit breaker in the fully open position opened.

In Figure 5, after a rotation of about three quarters of a turn of the control shaft 24, always in the same direction (see arrow F), the circuit breaker D is being closed and the second fixed and mobile contacts 2, 4 begin to close. When rotating the arm 9, the lug 17 associated with the rod 13 is driven by the edge 16a of the aforementioned light 16 so as to move the rod 13 upwards, and thus close the third fixed contacts and mobile 6, 7 of the bulb 5, (as shown in FIG. 6), before the closing of the first fixed and mobile contacts 1, 2, which allows the switching of the arc associated with first contacts 1, 3, as shown in Figure 7. Note that the closed position of the bulb S during the closing of the circuit breaker D is maintained for a period substantially equal to that during which the bulb S is maintained when the circuit breaker D. It will also be noted that the control shaft 24 always rotates in the same direction (arrow F), both for opening and closing of circuit breaker D.

The relative positions of the different contacts, as described above are particularly illustrated in FIG. 8 in which is represented in (1), the state of the first fixed and mobile contacts 1,3, in (2) the state of the second fixed and mobile contacts 2,4, in (3) the state of the contacts 6,7 of the vacuum interrupter 5 and in (4) the state of the circuit breaker.

We will now briefly describe the operation of an embodiment of the the invention, with reference to Figures 9 to 15. This operation is similar to that of previously described circuit breaker, except that it includes an additional step of earthing, at the end of the opening cycle, and that the closing of switch I is performed by rotation of the control shaft 24 in a direction opposite to that corresponding to the opening.

In FIG. 9, the switch I is in the fully closed position, the first and second contacts 1, 2, 3, 4 being closed, while the third fixed and mobile contacts 6.7 of the vacuum interrupter S are open. In FIG. 10, after a rotation of the shaft of control 24 in the opening direction (see arrow F in Figure 9), the switch I is in the open position. Note that the intermediate opening stages are not illustrated, because they correspond to those of the circuit breaker previously described.

In FIG. 11, it can be seen that an additional rotation of the control shaft 24 always in the same direction brought the two arms 8, 9 of the driving bridge P respectively in contact with the fourth and the fifth fixed contact 20, 21. It will be noted that during this movement, the lug 17 associated with the rod 13 has moved to the bottom 16th of the groove 16, the vacuum interrupter 6,7 remaining open. In this switch position, everything the downstream electrical circuit connected to terminal B is connected to earth T.

Referring to FIG. 15, it will be noted that the state of the contacts during the steps the opening of the switch corresponds exactly to that of circuit breaker D.

In FIG. 12, after a rotation of the control shaft 24 in the closing direction (opposite to the opening direction), the first fixed and movable contacts 1,3 begin to close, which causes the lug 17 towards the edge 16a of the light 16, which does not generate no effect on the rod 13. In FIG. 13, contact is established between the first contacts fixed and mobile 1, 3, and the contact between the second fixed and mobile contacts 2, 4 is initiated, the second arm 9 starting to drive the rod 13 upward through the edge 16a. After the complete closure of the first and second contacts 1,2,3,4, the third fixed contact and the third mobile contact 6, 7 close (Figure 14), then open new, automatically recalled to the open position by the spring 14.

It will be observed that the operation of the switch I, during closing, is the same than that of circuit breaker D, except that in the case of the switch, the first fixed and mobile contacts 1 and 3 close before closing the bulb 5 and second fixed and mobile contacts 2, 4.

The operation of the second embodiment of the switch I of the invention, with reference to FIGS. 16 to 20 and to the operating diagram of the Figure 15 in which is represented in (1) the state of the first contacts 1,3, in (2), that of seconds 2,4, in (3) that of the contacts 6,7 of the bulb, in (4), grounded through the closure of contacts 3, 20 on the one hand and 4, 21 on the other hand and in (5) the state of switch I.

In FIG. 16, the switch I is in the closed position, the first and second contacts 1, 3 and 2, 4 being closed, while the third fixed and movable contacts 6, 7 are recalled in spring open position 14.

In FIG. 17, a rotation of the control shaft 24 along the arrow F visible on the Figure 16, resulted in an opening of the two arms 28, 29 of the bridge P, so that the first 28 of the arms 28, 29 remains in contact with the first fixed contact 1, while the contact mobile 4 of the second arm 29 is no longer in contact with the second fixed contact 2. During this rotation, and prior to the opening of the second fixed and movable contacts 2, 4, the displacement of the cam 15 carried by the second arm 29 causes the displacement towards the top of the rod 13 associated with the movable contact 7 of the vacuum interrupter 5 causing the closing of the third fixed and movable contacts 6, 7. After an additional rotation of the control shaft 24, the contacts 6, 7 of the vacuum interrupter 5 open, taking into account the displacement of the cam 15 and of the return action of the spring 14 then the second contacts 2, 4 open further as the first contacts 1,3 begin to open.

In figure 19, all the contacts are open, which brings the switch I in position opened. Figure 20 illustrates the next step in grounding. The functioning of the switch I during closing being the same as that of the first embodiment described, these closing steps will not be described.

Finally, we will briefly describe the different stages of opening the circuit breaker D in accordance with the embodiment described in Figures 21 to 21c below. In figure 21 the circuit breaker D is in closed position, its fixed and movable contacts being closed. In Figure 2 la, the contacts 6, 7 of the vacuum interrupter close and the second fixed 2 and movable 4 contacts open, the first 1, 3 remaining closed. In FIG. 21b, the contacts 6, 7 of the vacuum interrupter 5 open, cutting off then the first contacts 1, 3 open. And in figure 21c all contacts are open.

Thanks to the invention, a circuit breaker and a switch of simple design have therefore been produced. and of reduced size, on the one hand that the various commands are carried out by the same control member, and secondly, that the structure of the switch allows the use of a small vacuum interrupter, because the length of time it holds the steady current is very short.

Claims (12)

1. A medium-voltage electrical switch comprising a sealed enclosure filled with a dielectric gas in which there are housed a first stationary contact (1) electrically connected to a first connection terminal, a second stationary contact (2) electrically connected to a second connection terminal, a mobile conducting bridge (P) equipped with a first and a second movable contact (3, 4) designed to cooperate respectively with the first and second stationary contacts and an operating mechanism (M) coupled to said bridge to make or break the electrical circuit between the first and second connection terminals, characterized in that it comprises in addition a vacuum cartridge (5) containing a third stationary contact (6) electrically connected to one (B), called the second, of the two connection terminals (A, B), and a third movable contact (7) electrically connected to said bridge (P) at an intermediate point situated between the first and second movable contact (3, 4) and mechanically coupled to said operating mechanism (M), and sequencing means designed to establish the opening and closing sequences of the first, second and third movable contacts (3, 4, 7) associated to the first, second and third stationary contacts (1, 2, 6), operating in conjunction with the above-mentioned operating means (M), in such a way that in the stable open or closed position of the switch (I), the third stationary contact (6) and movable contact (7) are separated, and that in the course of the opening or closing operations of the switch (I), the third stationary contact (6) and movable contact (7) close momentarily to switch the arc associated to the first stationary contact (1) and movable contact (3) or to the second stationary contact (2) and movable contact (4).
2. The switch according to claim 1, characterized in that said bridge (P) is rotary.
3. The switch according to one of the claims 1 or 2, characterized in that said bridge (P) comprises two distinct opposite arms (8, 28; 9,29), a first arm (8, 28) one of whose ends is equipped with said first movable contact (3) and whose other end is pivotally mounted around a spindle (X), and a second arm (9, 29) one of whose ends is equipped with said second movable contact (4) and whose other end is pivotally mounted around said spindle (X).
4. The switch according to claim 3, characterized in that said operating mechanism (M) comprises a crank (10) linked in rotation to a drive shaft (24), and a first and a second connecting rod (11, 12) coupled by one of their ends to the crank (10) and by their other end respectively to the first arm (8, 28) and the second arm (9, 29).
5. The switch according to any one of the claims 1 to 4, characterized in that the above-mentioned first terminal (A) is an input terminal strip and the above-mentioned second terminal (B) is an output terminal strip.
6. The switch according to any one of the claims 1 to 5, characterized in that the above-mentioned sequencing means are adapted to keep the third stationary and movable contacts (6, 7) separated in the stable position of the switch (I), and to close these two contacts (6, 7) in the course of opening of the switch (I), prior to separation of the second stationary and movable contacts (2, 4), and, in the course of closing of the switch (I), after closing of the second stationary and movable contacts (2, 4).
7. The switch according to any one of the claims 1 to 6, characterized in that said above-mentioned sequencing means include an extended fixed terminal strip (1a) provided on the above-mentioned first stationary contact (1), remaining in contact with said first movable contact (3) over a preset travel of said first movable contact (3), and a reduced fixed terminal strip (2a) provided on the second stationary contact (2) and not remaining in contact with said second movable contact (4) over a preset travel of the latter, when movement thereof takes place.
8. The switch according to any one of the claims 3 to 7, characterized in that the third movable contact (7) is supported by a rod (13) movable in translation which is biased by spring means (14) in the opening direction of the third stationary and movable contacts (6, 7), said rod (13) cooperating with means provided on the above-mentioned arms defining the opening and closing sequencing of the above-mentioned third stationary and movable contacts (6, 7).
9. The switch according to claim 8, characterized in that the above-mentioned means comprise at least one cam (15) securedly united to the first arm (28) or the second arm (29) whose profile defines the above-mentioned sequencing.
10. The switch according to claim 8, characterized in that the above-mentioned means comprise an aperture (16) arranged in one (8) of the arms (8, 9) cooperating with a spigot (17) securedly united to a connecting rod (18) connected in articulated manner via one (18a) of its ends to the above-mentioned rod (13), and via its other end (18b) to a crank (19) mounted free in rotation on the above-mentioned spindle (X).
11. The switch according to claim 10, characterized in that the above-mentioned aperture (16) is of arched shape and comprises a notched recess (16f) so as to form two portions of aperture (16b, 16c) of different widths.
12. The switch according to any one of the claims 3 to 11, characterized in that it comprises in addition a fourth stationary contact (20) which is connected to the earth (T), which is diametrically opposite the second stationary contact (2) with respect to said spindle (X) and a fifth stationary contact (21) electrically connected to said second terminal (B) which is diametrically opposite the first stationary contact (1) with respect to said spindle (X), said fourth and fifth stationary contacts (20, 21) operating respectively in conjunction with the first and second movable contact (3, 4) in the earthed position of the switch.

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