EP0758138B1 - Circuit breaking fuse and disconnect switch - Google Patents

Abstract

The three-phase fuse comprises, for each phase terminal, a cylindrical insulating envelope (1) inside which there is a vacuum ampoule (10). The envelope is provided with contacts (5,5') connected to the two terminals of the vacuum ampoule respectively and cooperating with a bar (97B) forming part of a set of bars and a cable input (95B). The envelopes are fixed to a common hollow support beam (31) comprising a shaft (39) solidly attached to a control (70) for the operation of the vacuum ampoules. Each vacuum ampoule is electrically connected in series with a circuit breaker attached to the envelope and arranged parallel to the axis of the envelope.

Description

The present invention relates to a ruptured fuse disconnector for the equipment of medium cells voltage.

State of the art

The combination of a switch and a circuit breaker, such as a fuse, has been known for a long time in medium voltage switchgear.

This association has been used for a long time, because it is economical to equip a busbar start when the nominal current is relatively low, but the relatively high short-circuit current.

For example, the nominal current I _N is less than or equal to 200 A while the short-circuit current I _cc is of the order of 25,000 A. This situation is frequently encountered in medium distribution voltage and in particular in the transformer protection cells.

In an association of this kind, it is the circuit breaker which cuts the short-circuit current on one or two phases and, after a short time, the circuit breaker opens the associated switch to cut the current limited by the circuit breaker.

This solution to limit the current has an advantage over other components of a medium voltage cell, such as transformers, cables, etc ..., which can be dimensioned in this way less important, which results in an economy on the cost of the cell.

The switch-circuit breaker association, called also "rupto-fuse" solution, for the protection of a medium voltage start, compare to the solution of using a circuit breaker, which is much more expensive.

• l'encombrement de l'interrupteur auto-pneumatique dans l'air,
• des efforts à fournir pour sa manoeuvre,

The rupto-fuse technique achieved wide commercial success for around thirty years (1950 to 1980), then gradually faded due to several factors, including:

• the size of the auto-pneumatic switch in the air,
• efforts to provide for its maneuver,

Subsequently, after replacing the switches to cut-off in air by cut-off switches in the SF6 gas (sulfur hexafluoride), including the breaking capacity is relatively weak, we encountered difficulties for coordinate them with circuit breakers.

The appearance of vacuum ampoules, especially low-end vacuum bulbs, easy to maneuver, relatively high breaking capacity in a small volume, can be easily associated and coordinated with a circuit breaker, allows to consider a new association economical, space-saving, reliable and very efficient.

The breakers were almost always associated with an upstream isolation switch.

The appearance of cells with self-disconnecting circuit breakers, described in particular in the patent application n ° 92 401 818, and marketed by the company GEC ALSTHOM T&D under the registered trademark "VISAX", provides a education that can be used to consider the design of a new breaker fuse.

Purpose of the invention

An object of the invention is to produce a rupto-fuse economical, equipped with small vacuum ampoules to achieve a full range of devices that can equip all medium voltage cells.

Another object of the invention is to produce a rupto-fuse can be integrated into the product range "VISAX" thanks to its installation in an extractable drawer identical to that of "VISAX" cells and interchangeable with the latter. This arrangement allows the electrical isolation by a simple rotation of 90 degrees.

Another object of the invention is to produce a rupto-fuse fully automatable, i.e. whose "cut" and "sectioning" functions can be chained and remotely controlled.

Another object of the invention is to produce a rupto-fuse economical, in particular thanks to the use of light bulbs vacuum of trade and already existing sub-assemblies, in particularly in the equipment of "VISAX" cells.

Definition of invention

The subject of the invention is a breaker fuse as defined in claim 1.

A device as described in the preamble of claim 1 is known from patent document EP-A-0 543 683.

List of Figures

• la figure 1 est une vue en élévation d'un pôle d'un rupto-fusible triphasé associé à un relais électromagnétique à haute tension,
• la figure 2 est une vue en perspective d'un rupto-fusible tripolaire monté en selon un module de type "VISAX".

The invention is clarified by the description of two modes of implementation of the mode invention, with reference to the appended drawing in which:

• FIG. 1 is an elevation view of a pole of a three-phase rupto-fuse associated with a high voltage electromagnetic relay,
• FIG. 2 is a perspective view of a three-pole rupto-fuse mounted in according to a "VISAX" type module.

Description of two embodiments of the invention

Figure 1 represents a pole of the rupto-fuse of the invention. It must be understood that a three-phase device has three identical poles, arranged one at a time compared to others in the manner which will be described later.

The breaker pole of Figure 1 includes a substantially cylindrical insulating jacket 1, preferably in molded epoxy resin, fitted with fins 2. At each of ends of the envelope, a closing plate, respectively 3 and 3 ', fixed by bolts 4, 4', serves as support for contact parts 5, 5 'which can cooperate respectively with a busbar and a cable head not represented.

Inside the envelope is placed a light bulb. empty 10; a fixed terminal 11 of the vacuum interrupter is connected electrically, by a conductor 12 embedded in the material of the envelope, to a first jaw 21 fixed externally to the envelope and intended to receive a circuit breaker; a second terminal 13, mobile, of the vacuum interrupter, constituted a rod passing through the wall of the vacuum sealed, is electrically connected by a contact sliding 14, to plate 4 'contact support 5'.

A second jaw 22, fixed to the upper part upper part of the casing 1, cooperates with the jaw 21 to receive a circuit breaker (fuse) 24. The jaw 22 is electrically connected to the plate 4 by a conductor 15.

The casing 1 is fixed, by screws 30, to a beam hollow metal 31, grounded; this metal beam supports the homologous envelopes of the two other poles of the device. In the example described, the beam is movable in rotation about its own axis, so that a rotation 90 degree angle allows you to move from the " service "in the" sectioning "position. This beam plays the same role as the similar beam of self-disconnecting circuit breakers of the aforementioned European patent application to which the reader is referred for further information.

Opening or closing the vacuum interrupter 10 are ensured by an order involving a chain kinematics, as described in the patent application mentioned above. The order can be an order to spring with hooking in closed position. This command, represented by the dashed rectangle 70 of the figure, is fixed to the end of the beam 31 and turns in same time as this during an operation of sectioning of the device. The control is of the rotary type or rickshaw. In the example in Fig. 1, the command is of the rotary type.

The kinematic chain includes an articulated arm 33 on the one hand at a point 34 fixed relative to the envelope and on the other hand, by a hinge 35, at the end of the rod 13. The arm 33 is articulated at 36 to an insulating rod 37 itself connected by a connecting rod 38, to a rotary shaft 39, arranged in the hollow beam 31 and connected to the control 70. The shaft 39 is common to the three poles of the device. The rotation around its axis of the shaft 39 under the action of the command 70, ensures simultaneous opening (or closing) of the three vacuum interrupters of the three-phase rupto-fuse.

In the embodiment described with reference to the Figure 1, the device is completed by a relay electromagnetic low voltage 40, arranged and fixed to inside the envelope. Relay 40 includes a shaft 41, the rotation of which also allows maneuvering rotation of the shaft 39, thanks to a kinematic chain comprising a connecting rod 42, an insulating rod 43 passing through an appropriate opening of the envelope 1, and a connecting rod 44.

• soit en raison d'une surcharge de courant détectée par une bobine 50 reliée aux bornes 3 et 3' de l'appareil,
• soit en raison de la fusion du fusible 24 qui est équipé d'un indicateur de fusion 60 dont le mouvement est transmis avec amplification au relais 40 par une tringle pivotante 61.

The shaft 41 can be operated:

• either due to a current overload detected by a coil 50 connected to terminals 3 and 3 'of the device,
• either due to the blowing of the fuse 24 which is equipped with a blowing indicator 60 whose movement is transmitted with amplification to the relay 40 by a pivoting rod 61.

• en cas de surcharge, détectée par la bobine 50, le relais 40 provoque la manoeuvre de l'arbre 41 entraínant l'ouverture des ampoules à vide.
• en cas de court-circuit, le fusible 24 fond et provoque la manoeuvre du relais grâce au détecteur de fusion 60, ce qui entraíne l'ouverture des ampoules à vide.

The operation of the rupto-fuse is as follows:
in normal operation, the vacuum interrupter is closed and the current flows through the contact 5 ', the plate 3', the rod 13 the contact 11, the conductor 12, the fuse 24 the connection 15, the plate 3 and the contact. The operation of the control 70 causing the rotation of the shaft 39 causes the opening of the vacuum ampoules; the rotation of the hollow shaft 31 by 90 ° allows the device to be cut.

• in case of overload, detected by the coil 50, the relay 40 causes the operation of the shaft 41 causing the opening of the vacuum interrupters.
• in the event of a short circuit, the fuse 24 blows and causes the relay to operate using the melting detector 60, which causes the vacuum bulbs to open.

The rupto-fuse of the invention can be placed in a drawer removable from a "Visax" type cell, which allows easy and safe maintenance.

Fig. 2 illustrates a variant implementation of the invention and represents, in perspective, the rupto-fuse assembly complete assembled according to a "VISAX" type module.

Reference 71 designates a tubular chassis, provided with casters 72, intended to be placed, in the manner of a drawer extractable, in a cabinet not shown.

A horizontal beam 74 is articulated by its two ends to plates 75A and 75B fixed to the chassis, so that you can rotate 90 ° around its longitudinal axis. Beam 74 is at earth potential.

To the beam 74 are fixed three poles 77A, 77B and 77C, each constituted as the pole of Fig. 1, to this close that they do not contain an electromagnetic relay 40. The circuit breakers are referenced 78A, 78B and 78C associated with the respective poles and connected in series with the respective vacuum interrupters. For clarity of design, the pole 77C has only been partially shown in lines dashed; only the bulb 79B of the pole 77B has been shown.

Sheltered from beam 74, a shaft 80 of command to open and close the poles, which can be actuated by rotation or by translation.

In the example of FIG. 1, this tree 80 is a tree of the "rickshaw" type, since it acts by moving in translation along its own axis, under the action an electromagnet coil 82; the control mechanism of the poles is explained with reference to pole 77B: the rod mobile 82B of the vacuum interrupter 79B is connected to a first end of a 83B metal rod articulated around a axis integral with the crossing 77B; the second end of the rod 83B is articulated at a first end of a 85B insulating rod capable of withstanding the voltage of operation of the device; the second end of the 85B insulating rod is articulated in a light of a first end of a 88B metal bracket whose second end is articulated on the control shaft 80. The square 88B pivots around an axis 90B secured to the beam 74. The translational movement along its axis of the shaft 80 causes the rotation of the bracket 88B and this movement is communicated to the control rod 82B by the connecting rods 85B and 83B.

Note that the tree 80 preferably has a section rectangular in its part between the joints, to allow easy attachment of brackets; on both sides of these joints it has preferably a circular shape, to slide freely at through plates 75A and 75B.

Note that the control shaft 80 for operating the bulbs is housed inside the joints of the beam 74, shaft 80 moving in translation while independently of the rotational movement of the beam 74.

The pole 77B has a first outlet 94B cooperating with a 95B current supply, and a second socket 96B cooperating with a bar 97B. The others poles have the same sockets cooperating with the same homologous elements. Insulating covers such as 99C provide insulation between the poles.

The device is cut off by a rotation the axis 80 which brings with it the poles and their fuses attached to it. For this, a 100 motor fixed to plate 75A drives a shaft 101 provided with a pinion 102 cooperating with a pinion 103 wedged on the shaft 80.

It should be noted that fuses 78A, 78B and 78C are provided a not shown fusion indicator which can activate a relay not shown controlling the supply of the motor 100 and that of the electromagnet 82.

The operation of the disconnecting fuse is the next:

In normal operation, the device is in the configuration of Fig. 2.

In the event of an overload, the relay controls the supply of the electromagnet which activates the rickshaw mechanism opening the vacuum ampoules.

One or more of the fuses in the event of a short circuit 78A to 78C fond and their command fusion indicator, to through the relay, power to the motor 100. The assembly starts spinning around the tree 80 and after a run limited (for example 20 degrees of rotation), the relay, provided an adequate time delay, controls the supply of the electromagnet 82 causing the bulbs to open at vacuum which then only have to cut a current limited by the fuses.

The complete rotation (90 degrees) of the assembly completes sectioning while atmospheric pressure causes the vacuum interrupters to close as soon as the power of the electromagnet has stopped.

After the fault has been rectified, the blown fuses are replaced; this operation is carried out simply and in all security by extracting the assembly which as it was said, form a drawer. After replacing the drawer, the assembly is returned to service by a rotation of 90 degrees obtained thanks to the 100 motor. The closing power is unnecessary due to the presence of circuit breakers.

It will be noted that the rupto-fuse of the invention is very economical, since vacuum bulbs can be used reduced performance.

For example, in a circuit breaker, the price of bulbs and the order would be around 12,000 F.

In a rupto-fuse of the invention, the price of vacuum bulbs and seriat relay of around 3000 F.

Assuming the costs of other accessories be the same in both solutions, we see that the solution of the invention allows savings on the order of 8000 to 9000 F, which is very important in big industry applications.

To this economy is added, in the version of the Fig. 2, a large part of the cost of the order.

A rough and not optimistic calculation allows us to think that, apart from protective relaying, the gain achievable for a transformer protection cell by rupto-fuse disconnector with respect to the equivalent cubicle equipped with a circuit breaker is around 30 to 40%.

It must also be taken into account that due to the presence of circuit breakers associated with a overload, secondary protection of the cell with rupto-fuse is reduced to its simplest expression, hence substantial additional gains.

Claims (3)

1. Three-phase switch-fuse comprising, for each pole, a substantially cylindrical insulative enclosure (1) inside which is a vacuum switching chamber (10), the enclosure being provided with contacts (5, 5') connected to respective terminals (11, 13) of the vacuum switching chamber and respectively cooperating with a substation (97B) and a current feeder (95B), the enclosures being fixed to a common hollow beam (31, 74) including a shaft (39, 80) attached to an actuator (70, 82) for operating the vacuum switching chambers, each vacuum switching chamber being electrically connected in series with a fuse (24) attached to the enclosure and disposed parallel to the axis of the enclosure, characterized in that each pole further comprises an electromechanical relay (40) provided with means for actuating said shaft (39), said means being actuated by a detector (60) which detects blowing of the fuse (24) and an overload detector coil (50).
2. Switch-fuse according to Claim 2, characterized in that said electromechanical relay (40) is housed inside and fixed to the inside of the insulative enclosure (1).
3. Switch-fuse according to Claim 1, characterized in that said shaft (80) is of the pull-push type operated by an electromagnet (82), the beam (74) is rotatable about its axis and driven by a motor (100), said motor (100) is controlled by a relay operated by a "fuse blown" detector and said relay operates said solenoid (82) after a time-delay.

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