EP2466611A1 - Electrical protection device comprising the differential protection function - Google Patents

Abstract

The apparatus e.g. bipolar modular differential circuit breaker (A), has phase and neutral disconnecting modules (1, 2) and a differential protection module (B) mounted on a rail. A core (6) is positioned within the protection module such that a center part of a coil is located between an axial plane of the core parallel to an initial direction of movement of electric arc and passing via a separation point of main contacts of one of the disconnecting modules, and another axial plane of the core located at 45 degrees with respect to the former plane from a side of a disconnecting chamber.

Description

The present invention relates to an electrical protection apparatus comprising the differential protection function, said electrical apparatus comprising at least one cut-off device of a phase and / or neutral and a differential protection device, said devices being juxtaposed laterally and mounted on the same mounting bracket as a rail, each switching device having two main contacts, said main contacts being closed during normal operation of the device and able to be opened so as to interrupt the current in the event of an incident on an electrical circuit, and a breaking chamber to which the arc is displaced as soon as the contacts are separated, said differential protection device comprising a toroid extending in a plane extending substantially perpendicular to the direction of alignment of the devices, the axis of the orifice of the torus being parallel to the axis of alignment of the devices said toroid being adapted to receive a number of so-called primary winding and a so-called secondary winding of measurement of the fault current, the number of primary windings corresponding to the number of electric breaking devices, the primary windings being formed by winding around the toroid of primary conductors each connecting an output terminal of a cut-off device to a contact pad of the differential protection device.

Differential circuit breakers are known comprising, in a manner known per se, a circuit breaker associated with a differential protection module. The circuit breaker is an electromagnetic or electronic protection device whose function is to interrupt the electric current in the event of an incident on an electrical circuit by opening the main contacts of said circuit breaker. It is capable of interrupting an overload current by means of thermal tripping means and a short-circuit current by means of magnetic tripping means.

The differential protection module is able to ensure the protection of people, ensuring a trip in case of abnormal current leakage. This differential protection module comprises a toroidal magnetic circuit on which are wound one or more phase and neutral circuits, called primary circuits, and a so-called secondary circuit constituting a fault current detection coil.

In the absence of leakage or residual fault current, the flows produced by the coils of the primary circuit are canceled, nothing happens. If a fault occurs, the residual fault current produces an unbalance in the flows in the primary circuit coils and a magnetic flux appears in the toroid. The measuring coil is the seat of electromagnetic energy that supplies an electromagnet causing the circuit breaker to unlock and open its main contacts.

As soon as the contacts are separated, the arc is moved towards the breaking chamber under the effect of the so-called Laplace force, induced by the geometry of the fixed and mobile contacts. During the journey between the contacts and the chamber, the bow is channeled between two cheeks which allow to increase its speed of movement, to guide its trajectory and to lengthen it.

In some cases, the torus is immediately next to the prechamber cut. The torus is provided with primary coils which are wound around its circumference and the lateral proximity of these coils negatively influences both the opening torque of the moving contact (direction, direction, point of application, influence of the environment) and on the propulsive force of the electric arc from birth and during its looping just before moving the arc in pre-chamber.

As a result, the arc hesitates and stagnates, and as a result, there is an increase in thermal stress. Thus, in order to obtain the desired cut-off performance, it would be useful to over-size the poles.

An artifice, to cancel the negative effect produced by the windings of the torus, could consist in adding a metal screen between the torus and the circuit breaker. But given the insufficient space to accommodate a metal screen of a significant thickness (at least 2 mm thick), this solution is not possible to cancel the negative effects of the primary coils. Finally, the cost of an additional piece to manufacture and manage is not feasible in an industrial context.

The present invention aims to improve the cut and to avoid the destruction of the pole of the circuit breaker which is adjacent to the differential protection block in short circuits.

For this purpose, the subject of the present invention is an electrical protection apparatus, this apparatus being characterized in that if we consider an observation direction defined by the three successive planes extending substantially perpendicularly to the plane of the torus and to the plan for fixing the apparatus, said planes respectively comprising successively the mobile contact (s), the fixed contact (s) and the interrupting chamber, the winding (s) on the toroid follows (r) the winding rule which consists in that the primary conductor coming from the output terminal electrically connected to the fixed contact of the said first breaking device, located closest to the differential protection device, is wound around of the torus in the counterclockwise direction, while the primary conductor from the output terminal electrically connected to the fixed contact of the second cutoff device located next to the cutoff device said pre the opposite side of the differential protection device, is wound around the toroid, in the direction of clockwise, in that the orifice of the torus is located opposite the partition separating the cutoff device said first of the differential protection device, and opposite the cut-off prechamber for receiving the electric arc, the aforementioned winding directions around the toroid being reversed if the output terminal (s) is (are) connected (s) ) electrically to the movable conductor (s), and in that the toroid is positioned inside the differential protection device such that the center of the first coil is between an axial plane of the core, said foreground, substantially parallel to the initial direction of movement of the arc and passing through the point of separation of the main contacts of at least one of the cut-off devices and an axial plane, said second, torus, located 45 ° with respect to this p first plane, on the side of the break chamber.

Thus, if the output terminal is connected to the moving contact in place of the fixed contact, then the reciprocal winding directions are reversed.

According to a particular embodiment, the apparatus is a modular apparatus, each switching device and the differential protection device being each disposed in a separable module or not other modules.

According to a particular characteristic, the toroid is placed inside the differential protection device, such that the axis of the toroid extends substantially parallel to the direction of alignment of the modules.

According to another characteristic, the separation points of the main contacts, associated respectively with the different cut-off devices are located on the so-called aforementioned first plane.

According to another characteristic, the number of electrical switching devices is two and comprises a phase cutoff device and a neutral cutoff device.

According to another characteristic, the number of electrical breaking modules is two and comprises a phase cutoff module and a neutral cutoff module.

According to another characteristic, the axis of the torus is substantially perpendicular to the side walls of the modules.

According to another characteristic, said apparatus comprising at least two coils connected respectively to two cut-off devices, this apparatus is characterized in that the center of the second winding is located opposite the center of the first winding with respect to the axis of the winding. toroid, such that these two windings are angularly offset by 180 ° relative to each other with respect to this axis.

According to another characteristic, the center of the measuring winding is located in an axial plane of the torus situated at approximately 45 ° with respect to the so-called first axial plane containing the center of the first winding.

The differential protection device is located to the left or right of the phase cut-off device and / or the neutral, the above-mentioned winding rule applies in the same way in the two aforementioned provisions if the output terminals are electrically connected to the same contacts.

According to another characteristic, the apparatus is a differential circuit breaker comprising at least one cutoff and / or neutral device and a differential protection device.

According to another characteristic, the device is a bipolar modular differential circuit breaker.

• La figure 1 est une vue en perspective, illustrant schématiquement un disjoncteur associé à un module de protection différentielle selon l'art antérieur,
• La figure 2 est une vue en perspective, illustrant schématiquement deux modules de coupure respectivement de phase et de neutre associés à un module de protection différentielle, toujours selon l'art antérieur, pendant la coupure,
• La figure 3 est une vue similaire à la figure 1, illustrant un disjoncteur associé à un module de protection différentielle selon une réalisation particulière de l'invention
• La figure 4 est une vue similaire aux figures 1 et 3, illustrant un disjoncteur associé à un module de protection différentielle selon une autre réalisation de l'invention,
• La figure 5 est une vue similaire à la figure 2, selon encore une autre réalisation de l'invention, pendant la coupure,
• La figure 6 est une vue partielle, illustrant suivant un plan parallèle à la profondeur des appareils, la chambre de coupure, les contacts principaux, le tore et ses bobinages, et
• La figure 7 est une représentation graphique illustrant en ordonnée, le couple d'ouverture en (N.M) du contact mobile en fonction de la position angulaire en degrés de l'une des bobines autour de l'axe du tore.

But other advantages and features of the invention will become more apparent in the detailed description which follows and refers to the accompanying drawings given solely by way of example and in which:

• The figure 1 is a perspective view, schematically illustrating a circuit breaker associated with a differential protection module according to the prior art,
• The figure 2 is a perspective view, schematically illustrating two respective phase and neutral cut-off modules associated with a differential protection module, still according to the prior art, during the cut-off,
• The figure 3 is a view similar to the figure 1 , illustrating a circuit breaker associated with a differential protection module according to a particular embodiment of the invention
• The figure 4 is a view similar to figures 1 and 3 , illustrating a circuit breaker associated with a differential protection module according to another embodiment of the invention,
• The figure 5 is a view similar to the figure 2 according to yet another embodiment of the invention, during the break,
• The figure 6 is a partial view, illustrating in a plane parallel to the depth of the apparatus, the breaking chamber, the main contacts, the toroid and its coils, and
• The figure 7 is a graphical representation showing, on the ordinate, the opening torque at (NM) of the moving contact as a function of the angular position in degrees of one of the coils around the axis of the torus.

On the figures 1 , 3 and 4 , a bipolar circuit breaker A is shown attached by one of its 3 side faces to a differential protection module B, the assembly being intended to be mounted on the same mounting bracket (not shown). This circuit breaker comprises two modules, respectively a phase cutoff module 1 said first, and a neutral cutoff module 2, said second. The output terminals of the circuit breaker A, 10.11 for the prior art and 14.15 for the device according to the invention are electrically connected to the terminals 9 of the differential protection device B after passing through a core 6 by so-called primary conductors 7,8, as regards the prior art and 12,13; 16,17; and 18,19 for the invention.

This core 6 extends inside the differential protection module in a plane parallel to the lateral faces 3,4,5 of the modules, its axis X extending parallel to the longitudinal direction of the fixing support and to the direction of alignment of the modules.

Thus, according to the prior art, as represented on the figures 1 and 2 the so-called primary conductors 7,8, one of which is a phase conductor and the other a neutral conductor, are introduced inside the core 6 by its face 6a situated on the side of the circuit-breaker A, then make the torus turn before being introduced again into the torus by the same side as before, then the conductors cross the torus a second time and emerge from the opposite side 6b thereof, after which the conductors are connected to the cores. 9 of the differential module B, said pads 9 being intended to receive the output terminals (not shown) of the differential module B.

In this embodiment of the prior art, the primary conductor 8 coming from the terminal 11 of the circuit breaker A situated furthest left in the figures, passes through the torus 6 in a direction opposite to that of the clockwise, while the primary conductor 7 from the terminal 10 to the right of the first, through the torus in the direction clockwise.

According to this embodiment, the son are as short as possible and has a minimum of folds. There is no crossing of wires between the terminals 10, 11 and the output of the core 6.

According to the three embodiments of the invention illustrated respectively on figures 3 , 4 and 5 the primary conductor 13,17,19 coming from the terminal 15 located in the so-called second clipping module 12 is wound on the core 6 in a clockwise direction, while the second conductor 12,16,18 from the terminal 14 of the breaking module 1 said first, is wound on the core 6 in a direction opposite to that of clockwise. Thus, according to the invention, the direction of rotation around the torus 6 of the primary conductors has been reversed with respect to the direction of rotation of the corresponding primary conductors of the apparatus according to the prior art.

According to the embodiment of the invention illustrated on the figure 3 the primary conductors 12, 13 are introduced inside the toroid by the face 6a of the torus 6 situated on the side of the circuit-breaker A, then go around the toroid, then go back over the torus and then leave the torus by the opposite face 6b to that located on the side of the circuit breaker. Thus, in this embodiment, the son are crossed at the output of the torus. But it will be noted that these wires could be crossed between the terminals 14,15 and the output 6a of the torus.

According to the embodiment of the invention illustrated on the figure 4 , the primary conductors 16, 17 are introduced inside the torus 6 by its face 6b located on the opposite side to the circuit breaker A, then go around the torus, then go back over the torus to leave it by its face 6a located the circuit breaker side to be connected to the pads 9 of the differential protection module B. In this embodiment, the son are folded but not crossed between the terminals 14,15 and the output of the core 6a.

According to the realization of the figure 5 the primary conductors 18, 19 are introduced into the core 6 by the face 6b thereof located on the opposite side of the circuit breaker, then pass through the core 6 and exit through the other face 6a, before going to connect on the 9 of the differential protection module.

According to the invention and as shown in the figure 6 , the axis X of the core is placed substantially perpendicular to the breaking chamber C. The first coil 21 is placed on the core 6 so that its center 22 is located between a first axial plane Q of the core 6 passing through the point Y of separation of the contacts 23,24 of the circuit breaker and a second axial plane R of the torus forming with the first plane Q an angle α of substantially 45 °. The center 26 of the second winding 25 (to be represented) is then in a diametrically opposite position with respect to the center 22 of the first winding 21, and the measurement winding (not shown) is in a position offset from the first primary winding 21 and of the second primary winding at an angle of substantially 90 °. According to this particular embodiment, this first axial plane Q of the torus is a plane passing through the device from the nose of the device to the fixing support and perpendicularly to this support.

Thus, according to the invention, the one 21 of the coils has been positioned in a precise zone opposite the point of separation of the contacts and it has been wound in a winding direction which makes it possible to create a magnetic field enabling the time to promote the electromagnetic force acting on the arc and leading to the arc chute, and also to increase the opening torque of the movable contact.

Advantageously, the face 6a of the toroid located on the side of the circuit breaker A is located closer to the separation wall 3 between the circuit breaker A and the differential protection module B, so as to reduce as much as possible the distance between the contacts and the torus. In order to exploit the torus environment to optimize the channeling of the magnetic field lines, any metallic element (shielding type) that may disturb the magnetic field of the toroid and placed between the toroid and the pole of the circuit breaker will be eliminated. Indeed, all the metal parts as well as the conductors contribute to a complex re-looping of the magnetic field lines and in particular, those produced by the winding of the torus.

Thus, thanks to the invention, a modification of the propulsion force is created on the cutoff arc in the direction of its displacement towards the breaking chamber. from the opening of the contacts (during the looping of the arc), then during its journey in the prechamber and up to the breaking chamber.

The circuit breaker is no longer in danger of being destroyed by the negative effects of the toroid winding field on the arc during short circuits

Indeed, if we have the winding in a traditional way, as illustrated on the figure 1 , the lateral parasitic component L is increased by a factor of 2 as shown in FIG. figure 2 , which has the effect of reducing the propulsion component T.

If, on the other hand, a winding according to the invention is carried out in a direction that is inverted with respect to the industrial direction, this lateral component L is canceled, and consequently the propulsion component T of the force on the arc towards the breaking chamber is thereby increased, its optimum value being reached for a recommended position corresponding to a maximum angle of 45 ° between the aforementioned first axial plane Q and the aforementioned second axial plane R, as illustrated in FIG. figure 7 which represents a characteristic curve of the gain obtained in inverse winding according to the invention, as a function of the angle between the two aforementioned planes. Indeed, in this figure, we see that when we have the winding on the circumference of the torus in different angular positions relative to the aforementioned first axial plane of the torus, in steps of 25 °, in positive and negative, we obtain a curve that has a very pronounced torque peak between 0 and 45 °.

It is the same for the opening torque exerted on the moving contact which is multiplied by a factor 3 with the inverted winding and positioning of the first coil in the recommended area (angle between 0 and 45 °).

Thus, according to the invention, the torus environment is exploited to optimize the channeling of the magnetic field lines so that they produce the beneficial effects on the electric arc and the moving contact.

On the other hand, the cut is improved compared to a solution of a differential block equipped with a shield.

Indeed, the effects of the field according to the invention improve the cutoff, while the solution with a screen restores it only. A gain on the opening torque of the movable contact is obtained by a factor of 3 and a cancellation of the parasitic side component, the gain then being 100%.

Of course, the invention is not limited to the embodiments described and illustrated which have been given by way of example.

On the contrary, the invention comprises all the technical equivalents of the means described and their combinations if they are carried out according to its spirit.

Claims (12)

Electrical protection device comprising the differential protection function, said electrical apparatus comprising at least one phase and / or neutral breaking device and a differential protection device, said devices being juxtaposed laterally and mounted on the same mounting bracket such a rail, each cut-off device comprising two main contacts, said main contacts being able to be closed during normal operation of the apparatus and able to be opened so as to interrupt the current in the event of an incident on a circuit electrical, and a breaking chamber to which the arc is moved from the separation of the contacts, said differential protection device comprising a torus extending in a plane extending substantially perpendicular to the alignment direction of the devices, the the axis of the orifice of the torus being parallel to the axis of alignment of the devices, said torus is ant intended to receive a number of so-called primary winding and a so-called secondary winding of measurement of the fault current, the number of primary windings corresponding to the number of electric breaking devices, the primary windings being formed by winding around the toroid of primary conductors each connecting an output terminal of a breaking device to a contact pad of the differential protection device, characterized in that if one considers an observation direction defined by the three successive planes extending substantially perpendicular to the plane of the torus and the plane of attachment of the devices, said planes respectively comprising successively the (the) contact (s) mobile (s), the (the) contact (s) fixed (s) and the cutting chamber, the (them) winding (s) on the torus follow the winding rule that is that the primary conductor (12,16,18) from the output terminal (14) electrically connected to the fixed contact of the disp first cut-off ostigiment (1), located closest to the differential protection device, is wound around the torus (6) counterclockwise, while the primary conductor (13,17,19) from the output terminal (15) electrically connected to the fixed contact of the second cut-off device (2) situated next to the so-called first cut-off device, on the side opposite to the differential protection device, is wound around the toroid (6) , in the sense of clockwise, in that the orifice of the torus is located opposite the partition (3) separating the so-called first breaking device (1) from the differential protection device B, and opposite the cut-off prechamber C intended to receive the electric arc, the aforementioned winding directions around the torus being reversed if the output terminal (s) is (are) electrically connected to the mobile conductor (s),
and in that the torus (6) is positioned inside the differential protection device such that the center (22) of the first coil (21) is between an axial plane Q of the torus, said foreground, substantially parallel to the initial direction of movement of the arc and passing through the separation point Y of the main contacts (23,24) of at least one of the cut-off devices and an axial plane R, said second, torus, located at 45 ° with respect to this first plane Q on the side of the interrupting chamber. Electrical protection device according to claim 1, characterized in that it is a modular device, each switching device (1, 2) and the differential protection device B being each arranged in a separable module or not other modules. Electrical protective device according to claim 1 or 2, characterized in that the core (6) is placed inside the differential protection device B, so that the axis X of the core (6) extends substantially parallel to the alignment direction of the modules. Electrical protection device according to one of Claims 1 to 3, characterized in that the separation points Y of the main contacts (23, 24) associated respectively with the different switching devices (1, 2) are located on the plane said first aforesaid Q. Electrical protection device according to any one of the preceding claims, characterized in that the number of electrical switching devices (1,2) is two and comprises a phase cut-off device and a neutral cut-off device. Electrical protection device according to any one of claims 2 to 5, characterized in that the number of electrical breaking modules is two and comprises a phase cutoff module and a neutral cutoff module. Electrical breaking device according to any one of claims 2 to 6, characterized in that the axis X of the core (6) is substantially perpendicular to the side walls (3,4,5) of the modules. Electrical protection device according to any one of the preceding claims, comprising at least two windings (21,25) connected respectively to two cut-off devices (1,2), characterized in that the center (26) of the second winding (25) ) is situated opposite that (22) of the first coil (21) with respect to the axis X of the core (6), so that the two coils are angularly offset by 180 ° with respect to the other, in relation to this axis. Electrical protection device according to any one of the preceding claims, characterized in that the center of the measuring coil is situated in an axial plane of the torus situated at approximately 45 ° with respect to the axial plane, referred to as the first Q, containing the center (22). the first winding (21). Electrical protection device according to one of the preceding claims, characterized in that the differential protection device is situated to the right or to the left of the phase cut-off device and / or the neutral, the above-mentioned winding rule applying in the same way in the two aforementioned provisions if the output terminals are electrically connected to the same contacts. Electrical protection device according to any one of the preceding claims, characterized in that it is a differential circuit breaker, comprising at least one cut-off device and / or neutral A and a differential protection device B. Electrical protection device according to claim 11 characterized in that it is a bipolar modular differential circuit breaker.

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