WO1988000390A1 - Fuse device for breaking a current - Google Patents

Fuse device for breaking a current Download PDF

Info

Publication number
WO1988000390A1
WO1988000390A1 PCT/FR1987/000243 FR8700243W WO8800390A1 WO 1988000390 A1 WO1988000390 A1 WO 1988000390A1 FR 8700243 W FR8700243 W FR 8700243W WO 8800390 A1 WO8800390 A1 WO 8800390A1
Authority
WO
WIPO (PCT)
Prior art keywords
cartridge
current
short
circuit
main fuse
Prior art date
Application number
PCT/FR1987/000243
Other languages
French (fr)
Inventor
Elie Belbel
Christian Blanchard
Thierry Boucheron
Michel Lauraire
Original Assignee
La Telemecanique Electrique
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by La Telemecanique Electrique filed Critical La Telemecanique Electrique
Publication of WO1988000390A1 publication Critical patent/WO1988000390A1/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/02—Details
    • H01H85/38—Means for extinguishing or suppressing arc
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/02—Details
    • H01H85/44—Structural association with a spark-gap arrester
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/02—Details
    • H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
    • H01H85/041—Fuses, i.e. expendable parts of the protective device, e.g. cartridges characterised by the type
    • H01H85/048—Fuse resistors
    • H01H2085/0486—Fuse resistors with voltage dependent resistor, e.g. varistor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/02—Details
    • H01H85/38—Means for extinguishing or suppressing arc
    • H01H2085/385—Impedances connected with the end contacts of the fusible element

Definitions

  • the present invention relates to a current interrupting device with a fuse cartridge for the protection of electrical equipment against overcurrents and short circuits.
  • the object of the present invention is to produce a device making it possible to cut off a presumed short-circuit current of value greater than the own breaking capacity of a given fuse cartridge, whatever the rating chosen for the latter.
  • the parent idea of the invention consists, from a so-called main fuse cartridge, in particular of the type described above, and of breaking capacity lower than the short-circuit current presumed to be cut, add in parallel an auxiliary assistance circuit to cut the short-circuit current, which is capable of increasing the breaking capacity of the main fuse cartridge used.
  • the cut-off assistance circuit according to the invention comprises:
  • said element consists of a spark gap
  • the current interruption means consist of a standard fuse cartridge mounted in series with the spark gap, of small caliber compared to the main fuse cartridge , and with breaking capacity at least equal to the presumed short-circuit current to be cut.
  • said element and the means for interrupting the current consist of a single varistor.
  • the main fuse cartridge assembly - assistance circuit to the breaking according to the invention ensures significantly faster breaking and therefore offers the advantage of lower thermal stress.
  • the cut-off assistance circuit is advantageously made with simple elements, compact and inexpensive; in the case of a main fuse cartridge of large caliber, the small space requirement and the moderate cost of the assistant circuit are particularly significant with regard to the production of a single fuse cartridge of large caliber and with appropriate breaking capacity.
  • Figures 1 and 2 show a fuse cartridge with knives in longitudinal section with its cut-off assistance circuit according to a first embodiment, under normal and respectively abnormal operating conditions of the circuit to be protected;
  • Figure 3 shows as a function of time the phenomena occurring during the operation of the overall device of Figure 2;
  • Figures 4 and 5 are views similar to Figures 1 and 2 for a variant of the cut-off assistance circuit
  • FIG. 6 shows the voltage-current characteristic of the varistor of FIGS. 4 and 5.
  • the same references refer to the same elements which fulfill the same functions for the same results.
  • a device 10 for interrupting current for the protection of an electrical installation comprises a fuse cartridge 12, known as a paleblade , of given size and breaking capacity, and an auxiliary cutting assistance circuit, designated by the general reference 15, mounted in parallel on the cartridge 12.
  • the fuse cartridge 12 is designed to be of high caliber, for example 1000 A - 1000 V, with a low breaking capacity, of the order of 15 A for the chosen caliber.
  • the main fuse cartridge 12 is of the knife type and comprises an insulating body 17 of parallelepiped shape, of central axis XX ′, and hollowed out of two longitudinal cylindrical cavities 19 and 20 parallel to the axis XX 1 , formed on either side 'other of this axis by communicating with each other at the level of axis XX'.
  • the two cavities 19 and 20 respectively house two hollow cylindrical pistons 23 and 24 made of insulating material and arranged so as to move in translation in opposite directions from one another under the effect of a propelling force. exerted on each of them, according to arrows A and B ( Figures 1 and 4).
  • the two pistons 23 and 24 each have on the front a central opening 25, respective ⁇ ment 26 and are pierced respectively with two lateral orifices 28 and 29 which communicate with each other at the ⁇ axis XX ' when the two pistons are in the rest position, as illustrated in Figures 1 and 4.
  • FIGS. 1 and 4 passes a fusible element constituted by a conductive strip 30, for example made of silver-plated copper, arranged perpendicular to the axis XX 'and clamped at each of its two ends between two fixed cylindrical conductive bars 32 and 33, respectively 35 and 36, housed respectively inside of the two pistons 23 and 24.
  • a fusible element constituted by a conductive strip 30, for example made of silver-plated copper, arranged perpendicular to the axis XX 'and clamped at each of its two ends between two fixed cylindrical conductive bars 32 and 33, respectively 35 and 36, housed respectively inside of the two pistons 23 and 24.
  • Each of the two bars 32 and 35 comes out slightly on the rear face of its corresponding piston and is fixed on a conductive plate 38, respectively 39, via an opening made in an insulating part forming a base 41, respectively. 42.
  • Each of the two other bars 33 and 36 is profiled so as to delimit, with its corresponding piston in the rest position (
  • the cartridge 12 also includes two knives 48 and 49 made of conductive material and fixed, for example by welding, respectively to the two plates 38 and 39, perpendicularly to them at the level of the axis XX '. It should be noted that each plate can also be made in one piece with its knife.
  • the 1000 A - 1000 V caliber fuse cartridge 12 as described above is capable, alone, of breaking a short-circuit current of 15 kA peaks.
  • the fusible blade 30 of the cartridge splits in two and the energy of the electric arc which is created is collected in the two internal spaces 44 and 45 and then exerts on each of the two pistons 23 and 24 a force which very quickly causes them to move axially in opposite directions to one another, so as to produce a shear of the arc.
  • a set of conduits (not shown) are provided in the cartridge to ensure the expansion of the gases propelling the pistons.
  • the circuit 15 connected between the two knives 48 and 49 of the main fuse cartridge 12 comprises in series a spark gap 56, of conventional structure, and a fast standard fuse cartridge 57, called auxiliary, of the cylindrical or knife type, with a filling of sand.
  • the spark gap 56 constitutes in itself an electrically insulating electrical element which is nevertheless capable of becoming conductive from a given threshold voltage, called ignition voltage, applied to its terminals, which will be defined below, while that the fuse cartridge 57 is adapted to rapidly interrupt the current flowing through the spark gap 56 when the latter becomes conductive.
  • the auxiliary cartridge 57 is chosen to be of a small caliber, that is to say of nominal current value clearly lower and of the same nominal voltage value, for example 100 A - 1000 V in the retained case of a main fusible cartridge capable of holding 1000 amperes at a maximum voltage of 1000 volts, and has a breaking capacity 5 greater than that of the main cartridge and at least equal to the short-circuit current presumed to be cut; by way of illustration, in the case of a presumed short-circuit current of 50 kA peaks and with a main cartridge of 15 kA breaking capacity, the auxiliary cartridge 57 10. used has a breaking capacity of 50 kA.
  • the Applicant has implemented this embodiment with an igniter and an auxiliary fuse cartridge in the case of a presumed short-circuit current of 50 kA peaks, using, on the one hand, a main fuse cartridge (with pistons ) of a 1000 A - 1000 V rating with a breaking capacity of 15 kA and, on the other hand, a conventional spark gap (ignition voltage selected at 250 V) and a standard (sand) standard auxiliary fuse cartridge 100 A - 1000 V with a breaking capacity of 50 kA: the breaking time recorded is around 6 milliseconds.
  • the circuit 15 for cutting assistance is simply constituted by a varistor 59, of conventional structure, made of zinc oxide for example, which is directly connected between the two knives 48 and 49 from the main fuse cartridge 12.
  • the varistor 59 is designed as a function of the presumed short-circuit current to be cut and it constitutes in itself an electronic element which, mounted in parallel on the fuse cartridge, alone fulfills the double function of being normally insulating, but likely to become conductive from a given threshold voltage applied to its terminals, on the one hand, and to quickly interrupt the short-circuit current, on the other hand.
  • FIG. 6 the shape of the voltage V applied to the terminals of the varistor 59 has been shown as a function of the current I, said varistor being of high value as long as its threshold voltage Vs' is not c reached.
  • the threshold voltage V ' is determined from the following conventional formula:
  • V R network voltage
  • V arc voltage
  • the operation is as follows. First of all, under normal operating conditions of the circuit, FIG. 4, the permanent current flowing through the line in the direction indicated by the arrow passes almost entirely through the fuse cartridge 12 which does not work, the varistor 59 being of high value for the very low voltage that appears across the cartridge.
  • the fuse cartridge can be equipped with a member called striker (not shown) which is adapted to cause, as soon as the the cartridge, the opening of a conventional microswitch arranged at the outlet of the varistor.
  • a fuse cartridge has therefore been produced according to the invention, the own breaking capacity of which is artificially increased by adding a breaking assistance circuit, which is of a particularly simple and inexpensive structure. It will be noted that the above description has been made with reference to a main fuse cartridge produced according to a piston version; of course, the invention also applies to any other structure of a fusible cartridge which guarantees total isolation during its operation.

Abstract

In order to break a short circuit current higher than the inherent breaking power of a fuse cartridge (12), there is added in parallel to the cartridge a breaking assistance circuit (15) which comprises a normally insulating element susceptible of becoming conductive from a given threshold voltage, comprised for example of an arrester (56) and means for breaking the current passing through said element, which means may be comprised of a standard fuse cartridge (57) having a high breaking power. Application: protection of high-power electric equipment.

Description

DISPOSITIF D'INTERRUPTION DE COURANT A FUSIBLE. FUSE CURRENT INTERRUPTION DEVICE.
La présente invention concerne un dispositif d'interruption de courant à cartouche fusible pour la protection des équi¬ pements électriques contre les surintensités et les courts- circuits.The present invention relates to a current interrupting device with a fuse cartridge for the protection of electrical equipment against overcurrents and short circuits.
On connaît déjà, d'après le brevet FR-2 576 451, une struc¬ ture de cartouche fusible qui est capable d'éteindre l'arc électrique créé lors de l'apparition d'un court-circuit en assurant un isolement total. Cette cartouche fusible compor- te à l'intérieur d'une enveloppe deux pistons isolants propulsés en sens inverse l'un de l'autre par l'énergie même de l'arc électrique pour venir occuper une position où l'arc est cisaillé, les deux pistons établissant en fin de course une distance d'isolement suffisamment grande pour empêcher tout réamorçage d'un arc.Already known, from patent FR-2 576 451, a structure of a fuse cartridge which is capable of extinguishing the electric arc created during the appearance of a short circuit while ensuring total isolation. This fuse cartridge has inside an envelope two insulating pistons propelled in opposite directions from each other by the very energy of the electric arc to come to occupy a position where the arc is sheared, the two pistons establishing at the end of the stroke a sufficiently large isolation distance to prevent any re-ignition of an arc.
Comme pour toute cartouche fusible, celle du genre mentionné ci-dessus est dimensionnée selon son calibre de manière à assurer un pouvoir de coupure donné.As with any fuse cartridge, that of the kind mentioned above is sized according to its rating so as to ensure a given breaking capacity.
La présente invention a pour but de réaliser un dispositif permettant de couper un courant de court-circuit présumé de valeur supérieure au propre pouvoir de coupure d'une cartou¬ che fusible donnée, quel que soit le calibre retenu pour cette dernière. A cet effet, l'idée mère de l'invention consiste, à partir d'une cartouche fusible dite principale, notamment du type décrit ci-dessus, et de pouvoir de coupure inférieur au courant de court-circuit présumé à couper, à lui adjoindre en parallèle un circuit auxiliaire d'assistance a la coupure du courant de court-circuit, lequel est capable d'augmenter le pouvoir de coupure de la cartouche fusible principale utilisée.The object of the present invention is to produce a device making it possible to cut off a presumed short-circuit current of value greater than the own breaking capacity of a given fuse cartridge, whatever the rating chosen for the latter. To this end, the parent idea of the invention consists, from a so-called main fuse cartridge, in particular of the type described above, and of breaking capacity lower than the short-circuit current presumed to be cut, add in parallel an auxiliary assistance circuit to cut the short-circuit current, which is capable of increasing the breaking capacity of the main fuse cartridge used.
Le circuit d'assistance à la coupure suivant l'invention comprend :The cut-off assistance circuit according to the invention comprises:
- un élément normalement isolant, mais susceptible de deve¬ nir conducteur à partir d'une tension de seuil donnée appliquée "à ses bornes de manière à dériver la totalité du courant de court-circuit immédiatement après le début du fonctionnement de la cartouche fusible principale ; et- an element normally insulating, but capable of becoming conductive from a given threshold voltage applied " to its terminals so as to derive the entire short-circuit current immediately after the start of operation of the main fuse cartridge ; and
- des moyens aptes à interrompre le courant passant dans ledit élément.- Means capable of interrupting the current passing through said element.
Selon un premier mode de réalisation, ledit élément est constitué par un éclateur, tandis que les moyens d'interrup¬ tion du courant sont constitués par une cartouche fusible standard montée en série avec l'éclateur, de faible calibre comparativement à la cartouche fusible principale, et à pouvoir de coupure au moins égal au courant de court-circuit présumé à couper.According to a first embodiment, said element consists of a spark gap, while the current interruption means consist of a standard fuse cartridge mounted in series with the spark gap, of small caliber compared to the main fuse cartridge , and with breaking capacity at least equal to the presumed short-circuit current to be cut.
Dans une variante d'exécution, ledit élément et les moyens d'interruption du courant sont constitués par une seule et même varistance.In an alternative embodiment, said element and the means for interrupting the current consist of a single varistor.
Il est important de noter que par rapport à une coupure de court-circuit qui serait réalisée au moyen d'une seule cartouche fusible de pouvoir de coupure approprié, l'ensem- ble cartouche fusible principale - circuit d'assistance à la coupure suivant l'invention assure une coupure nettement plus rapide et offre donc l'avantage d'une plus faible contrainte thermique.It is important to note that compared to a short circuit break which would be achieved by means of a single fuse cartridge of suitable breaking capacity, the main fuse cartridge assembly - assistance circuit to the breaking according to the invention ensures significantly faster breaking and therefore offers the advantage of lower thermal stress.
D'autre part, dans chacun de ses deux modes de réalisation décrits ci-dessus, le circuit d'assistance à la coupure est réalisé avantageusement avec des éléments simples, peu encombrants et peu coûteux ; dans le cas d'une cartouche fusible principale de fort calibre, le faible encombrement et le coût modéré du circuit adjoint sont particulièrement significatifs vis-à-vis de la réalisation d'une seule cartouche fusible de fort calibre et à pouvoir de coupure approprié.On the other hand, in each of its two embodiments described above, the cut-off assistance circuit is advantageously made with simple elements, compact and inexpensive; in the case of a main fuse cartridge of large caliber, the small space requirement and the moderate cost of the assistant circuit are particularly significant with regard to the production of a single fuse cartridge of large caliber and with appropriate breaking capacity.
D'autres caractéristiques et avantages de l'invention apparaîtront mieux dans la description détaillée qui suit et se réfère aux dessins annexés donnés uniquement à titre d'exemple et dans lesquels :Other characteristics and advantages of the invention will appear more clearly in the detailed description which follows and which refers to the appended drawings given solely by way of example and in which:
Les figures 1 et 2 montrent une cartouche fusible à couteaux en coupe longitudinale avec son circuit d'assistance à la coupure selon un premier mode de réalisation, sous des conditions normales et respec¬ tivement anormales de fonctionnement du circuit à protéger ;Figures 1 and 2 show a fuse cartridge with knives in longitudinal section with its cut-off assistance circuit according to a first embodiment, under normal and respectively abnormal operating conditions of the circuit to be protected;
La figure 3 montre en fonction du temps les phénomènes se déroulant lors du fonctionnement du dispositif global de la figure 2 ;Figure 3 shows as a function of time the phenomena occurring during the operation of the overall device of Figure 2;
Les figures 4 et 5 sont des vues analogues aux figures 1 et 2 pour une variante du circuit d'assistance à la coupure ; etFigures 4 and 5 are views similar to Figures 1 and 2 for a variant of the cut-off assistance circuit; and
La figure 6 montre la caractéristique tension - cou¬ rant de la varistance des figures 4 et 5. Sur ces différentes figures, les mêmes références se rappor¬ tent aux mêmes éléments qui remplissent les mêmes fonctions en vue des mêmes résultats.FIG. 6 shows the voltage-current characteristic of the varistor of FIGS. 4 and 5. In these different figures, the same references refer to the same elements which fulfill the same functions for the same results.
En se reportant aux figures 1 et 2 ainsi qu'aux figures 4 et 5, un dispositif 10 d'interruption de courant pour la protection d'une installation électrique, conforme à l'invention, comporte une cartouche fusible 12, dite princi¬ pale, de calibre et de pouvoir de coupure donnés, et un circuit auxiliaire d'assistance à la coupure, désigné par le repère général 15, monté en parallèle sur la cartouche 12.Referring to FIGS. 1 and 2 as well as to FIGS. 4 and 5, a device 10 for interrupting current for the protection of an electrical installation, in accordance with the invention, comprises a fuse cartridge 12, known as a paleblade , of given size and breaking capacity, and an auxiliary cutting assistance circuit, designated by the general reference 15, mounted in parallel on the cartridge 12.
A titre illustratif mais non limitatif, la cartouche fusible 12 est conçue pour être de fort calibre, par exemple 1000 A - 1000 V, avec un bas pouvoir de coupure, de l'ordre de 15 A pour le calibre choisi.By way of illustration but not limitation, the fuse cartridge 12 is designed to be of high caliber, for example 1000 A - 1000 V, with a low breaking capacity, of the order of 15 A for the chosen caliber.
La cartouche fusible principale 12 est du type à couteaux et comporte un corps isolant 17 de forme parallélépipédique, d'axe central XX' , et creusé de deux cavités longitudinales cylindriques 19 et 20 parallèles à l'axe XX1, ménagées de part et d'autre de cet axe en communiquant l'une avec l'autre au niveau de l'axe XX'.The main fuse cartridge 12 is of the knife type and comprises an insulating body 17 of parallelepiped shape, of central axis XX ′, and hollowed out of two longitudinal cylindrical cavities 19 and 20 parallel to the axis XX 1 , formed on either side 'other of this axis by communicating with each other at the level of axis XX'.
Les deux cavités 19 et 20 logent respectivement deux pistons cylindriques creux 23 et 24 réalisés en matière isolante et disposés de manière à se déplacer en translation en sens inverse l'un de l'autre sous l'effet d'une force de propul¬ sion exercée sur chacun d'eux, selon les flèches A et B (figures 1 et 4) . Les deux pistons 23 et 24 présentent chacun en face avant une Ouverture centrale 25, respective¬ ment 26, et sont percés respectivement de deux orifices latéraux 28 et 29, lesquels communiquent l'un avec l'autre au niveau de lτaxe XX' lorsque les deux pistons sont en position de repos, comme illustré aux figures 1 et 4.The two cavities 19 and 20 respectively house two hollow cylindrical pistons 23 and 24 made of insulating material and arranged so as to move in translation in opposite directions from one another under the effect of a propelling force. exerted on each of them, according to arrows A and B (Figures 1 and 4). The two pistons 23 and 24 each have on the front a central opening 25, respective¬ ment 26 and are pierced respectively with two lateral orifices 28 and 29 which communicate with each other at the τ axis XX ' when the two pistons are in the rest position, as illustrated in Figures 1 and 4.
Par ces deux orifices latéraux 28 et 29 mis en communica¬ tion, figures 1 et 4, passe un élément fusible constitué par une lame conductrice 30, par exemple en cuivre argenté, agencée perpendiculairement à l'axe XX' et enserrée à chacu¬ ne de ses deux extrémités entre deux barreaux conducteurs cylindriques fixes 32 et 33, respectivement 35 et 36, logés respectivement à l'intérieur des deux pistons 23 et 24. Chacun des deux barreaux 32 et 35 sort légèrement en face arrière de son piston correspondant et est fixé sur une plaque conductrice 38, respectivement 39, via une ouverture ménagée dans une pièce isolante formant embase 41, respecti- vement 42. Chacun des deux autres barreaux 33 et 36 est profilé de manière à délimiter, avec son piston correspon¬ dant en position de repos (figures 1 et 4) , un espace interne 44, respectivement 45, de volume variable communi¬ quant avec l'orifice du piston.Through these two lateral orifices 28 and 29 placed in communication, FIGS. 1 and 4, passes a fusible element constituted by a conductive strip 30, for example made of silver-plated copper, arranged perpendicular to the axis XX 'and clamped at each of its two ends between two fixed cylindrical conductive bars 32 and 33, respectively 35 and 36, housed respectively inside of the two pistons 23 and 24. Each of the two bars 32 and 35 comes out slightly on the rear face of its corresponding piston and is fixed on a conductive plate 38, respectively 39, via an opening made in an insulating part forming a base 41, respectively. 42. Each of the two other bars 33 and 36 is profiled so as to delimit, with its corresponding piston in the rest position (Figures 1 and 4), an internal space 44, respectively 45, of variable volume communi¬ as to the orifice of the piston.
La cartouche 12 comporte également deux couteaux 48 et 49 réalisés en matériau conducteur et fixés, par exemple par soudage, respectivement aux deux plaques 38 et 39, perpendi¬ culairement à celles-ci au niveau de l'axe XX'. Il est à noter qu'on peut également réaliser d'une seule pièce chaque plaque avec son couteau.The cartridge 12 also includes two knives 48 and 49 made of conductive material and fixed, for example by welding, respectively to the two plates 38 and 39, perpendicularly to them at the level of the axis XX '. It should be noted that each plate can also be made in one piece with its knife.
Comme on l'a indiqué précédemment, la cartouche fusible 12 de calibre 1000 A - 1000 V telle que décrite ci-dessus est capable, seule, de couper un courant de court-circuit présu¬ mé de 15 kA crêtes. Ainsi, lors du développement d'un tel court-circuit, la lame fusible 30 de la cartouche se scinde en deux et l'énergie de l'arc électrique qui se crée est recueillie dans les deux espaces internes 44 et 45 et exerce alors sur chacun des deux pistons 23 et 24 une force qui provoque très rapidement leur déplacement axial en sens inverse l'un de l'autre, de manière à produire un cisaille¬ ment de l'arc.As indicated previously, the 1000 A - 1000 V caliber fuse cartridge 12 as described above is capable, alone, of breaking a short-circuit current of 15 kA peaks. Thus, during the development of such a short circuit, the fusible blade 30 of the cartridge splits in two and the energy of the electric arc which is created is collected in the two internal spaces 44 and 45 and then exerts on each of the two pistons 23 and 24 a force which very quickly causes them to move axially in opposite directions to one another, so as to produce a shear of the arc.
Les deux pistons 23 et 24 en fin de course, figures 2 et 5, viennent en butée sur des talons isolants (non figurés) portés par les embases 41 et 42, et leur mouvement est amorti sans rebondissement au moyen de plusieurs bagues annulaires en élastomère représentées en 52 sur les figures 1, 2, 4 et 5" * The two pistons 23 and 24 at the end of the race, FIGS. 2 and 5, abut on insulating heels (not shown) carried by the bases 41 and 42, and their movement is damped without rebound by means of several rings elastomer rings represented at 52 in FIGS. 1, 2, 4 and 5 " *
Il est- important de noter qu'en fin de course de chaque piston (figures 2 et 5) , la distance entre les deux parties de la lame fusible est suffisamment grande pour éviter tout réamorçage d'un arc entre ces parties de la lame, leur assu¬ rant ainsi un isolement total.It is important to note that at the end of the stroke of each piston (FIGS. 2 and 5), the distance between the two parts of the fusible blade is large enough to avoid any re-ignition of an arc between these parts of the blade, thus ensuring their total isolation.
De plus, un ensemble de conduits (non figurés) sont prévus dans la cartouche pour assurer la détente des gaz propulsant les pistons.In addition, a set of conduits (not shown) are provided in the cartridge to ensure the expansion of the gases propelling the pistons.
Dans le but de couper un courant de court-circuit présumé de valeur supérieure au propre pouvoir de coupure de la cartou¬ che fusible 12, conformément à l'invention, on adjoint en parallèle sur la cartouche 12 le circuit 15 d'assistance à la coupure que l'on va maintenant décrire.In order to cut a presumed short-circuit current of value greater than the own breaking capacity of the fuse cartridge 12, in accordance with the invention, the circuit 15 for assisting the cut which we will now describe.
Selon un premier mode de réalisation préféré, illustré aux figures 1 et 2, le circuit 15 connecté entre les deux couteaux 48 et 49 de la cartouche fusible principale 12, comporte en série un éclateur 56, de structure classique, et une cartouche fusible standard rapide 57, dite auxiliaire, du type cylindrique ou à couteaux, avec un remplissage de sable.According to a first preferred embodiment, illustrated in FIGS. 1 and 2, the circuit 15 connected between the two knives 48 and 49 of the main fuse cartridge 12, comprises in series a spark gap 56, of conventional structure, and a fast standard fuse cartridge 57, called auxiliary, of the cylindrical or knife type, with a filling of sand.
L'éclateur 56 constitue en soi un élément électrique norma¬ lement isolant qui est néanmoins susceptible de devenir conducteur à partir d'une tension de seuil donnée, dite d'amorçage, appliquée à ses bornes, que l'on définira plus loin, tandis que la cartouche fusible 57 est adaptée pour interrompre rapidement le courant traversant l'éclateur 56 lorsque celui-ci devient conducteur.The spark gap 56 constitutes in itself an electrically insulating electrical element which is nevertheless capable of becoming conductive from a given threshold voltage, called ignition voltage, applied to its terminals, which will be defined below, while that the fuse cartridge 57 is adapted to rapidly interrupt the current flowing through the spark gap 56 when the latter becomes conductive.
En comparaison de la cartouche principale 12 définie plus haut, la cartouche auxiliaire 57 est choisie d'un faible calibre, c'est-à-dire de valeur de courant nominal nettement inférieure et de même valeur de tension nominale, par exem¬ ple 100 A - 1000 V dans le cas retenu d'une cartouche fusi¬ ble principale apte à tenir 1000 ampères sous une tension maximale de 1000 volts, et présente un pouvoir de coupure 5 supérieur à celui de la cartouche principale et au moins égal au courant de court-circuit présumé à couper ; à titre illustratif, dans le cas d'un courant de court-circuit présumé de 50 kA crêtes et avec une cartouche principale de pouvoir de coupure de 15 kA, la cartouche auxiliaire 57 10. utilisée a un pouvoir de coupure de 50 kA.In comparison with the main cartridge 12 defined above, the auxiliary cartridge 57 is chosen to be of a small caliber, that is to say of nominal current value clearly lower and of the same nominal voltage value, for example 100 A - 1000 V in the retained case of a main fusible cartridge capable of holding 1000 amperes at a maximum voltage of 1000 volts, and has a breaking capacity 5 greater than that of the main cartridge and at least equal to the short-circuit current presumed to be cut; by way of illustration, in the case of a presumed short-circuit current of 50 kA peaks and with a main cartridge of 15 kA breaking capacity, the auxiliary cartridge 57 10. used has a breaking capacity of 50 kA.
En référence aux figures 1 à 3, le fonctionnement est le suivant.With reference to Figures 1 to 3, the operation is as follows.
15 Tout d'abord, dans des conditions opératoires normales de la ligne, figure 1, le courant permanent parcourant la ligne dans le sens indiqué par la flèche passe intégralement dans la cartouche fusible principale 12 qui ne fonctionne pas, l'éclateur 56 se comportant comme un isolant parfait vis-à- 0 vis de la'cartouche fusible auxiliaire 57 qui ne fonctionne donc pas.First of all, under normal operating conditions of the line, FIG. 1, the permanent current flowing through the line in the direction indicated by the arrow passes entirely through the main fuse cartridge 12 which does not work, the spark gap 56 behaving as a perfect insulator vis-à-vis 0 auxiliary fuse 57 that do not work.
Lorsqu'il apparaît un court-circuit d'intensité élevée supérieure au propre pouvoir de coupure de la cartouche 5 fusible principale 12, par exemple un courant de court- circuit présumé de 50 kA crêtes pour un pouvoir de coupure de ladite cartouche de l'ordre de 15 kA, dans un premier temps la cartouche principale 12 fonctionne selon le princi¬ pe exposé précédemment, ses deux pistons propulsés 23 et 24 0 (figure 2) établissant un isolement suffisant pour éviter tout réamorçage d'un arc.When a short circuit of high intensity appears greater than the own breaking capacity of the cartridge 5 main fuse 12, for example a presumed short-circuit current of 50 kA peaks for a breaking capacity of said cartridge of the order of 15 kA, initially the main cartridge 12 operates according to the principle described above, its two propelled pistons 23 and 24 0 (Figure 2) establishing sufficient isolation to avoid any re-ignition of an arc.
Sur la figure 3, on a illustré en traits pointillés la tension d'arc V qui se développe aux bornes de la cartouche 5 principale 12 et qui croît très rapidement après la période dite d'entrée en action ta_, et en traits pleins le courant I qui passe dans ladite cartouche et qui est limité rapidement par celle-ci après son entrée en action. En choisissant pour l'éclateur 56 une tension d'amorçage Vg (figure 3) inférieure à la tension d'arc maximale aux bornes de la cartouche fusible principale 12, presque dès l'entrée en action de cette dernière, la tension d'amorçage est appliquée aux bornes de l'éclateur 56 qui devient donc conducteur, de sorte que le courant de court-circuit passe en totalité dans le chemin dérivé que constituent l'éclateur 56 et la cartouche fusible auxiliaire 57 à pouvoir de coupu¬ re élevé ; le fusible auxiliaire 57 saute presque instanta¬ neirrenfc et coupe ainsi le court-circuit, comme illustré à la figure 2-In FIG. 3, the arc voltage V which develops at the terminals of the main cartridge 12 and which increases very rapidly after the period known as entry into action ta_ has been illustrated in dashed lines, and in current the current I which passes through said cartridge and which is rapidly limited by the latter after it comes into action. By choosing for the spark gap 56 an ignition voltage V g (FIG. 3) lower than the maximum arc voltage across the terminals of the main fuse cartridge 12, almost as soon as the latter comes into action, the voltage of ignition is applied to the terminals of the spark gap 56 which therefore becomes conductive, so that the short-circuit current flows entirely in the branch path that constitutes the spark gap 56 and the auxiliary fuse cartridge 57 with high breaking capacity ; the auxiliary fuse 57 almost immediately blows neirrenfc and thus cuts the short-circuit, as illustrated in figure 2-
Sur la figure 3, on a représenté en traits mixtes le courant I' qui passe dans l'éclateur 56 et la cartouche fusible 57 ; ce courant croît drabord très rapidement après une période tb légèrement supérieure à t , puis décroît après l'entrée en action de la cartouche fusible 57, la coupure étant réalisée après une durée totale t .In Figure 3, there is shown in broken lines the current I 'which passes through the spark gap 56 and the fuse cartridge 57; this current increases to r first very quickly after a period t b slightly greater than t, and then decreases after the entry into action of the fuse cartridge 57, the cut being carried out after a total duration t.
La Demanderesse a mis en pratique cette réalisation à écla¬ teur et cartouche fusible auxiliaire dans le cas d'un cou¬ rant de court-circuit présumé de 50 kA crêtes, en utilisant, d'une part, une cartouche fusible principale (à pistons) de calibre 1000 A - 1000 V avec un pouvoir de coupure de 15 kA et, d'autre part, un éclateur classique (tension d'amorçage choisie à 250 V) et une cartouche fusible auxiliaire stan¬ dard (à sable) de calibre 100 A - 1000 V avec un pouvoir de coupure de 50 kA : le temps de coupure relevé est de l'ordre de 6 millisecondes.The Applicant has implemented this embodiment with an igniter and an auxiliary fuse cartridge in the case of a presumed short-circuit current of 50 kA peaks, using, on the one hand, a main fuse cartridge (with pistons ) of a 1000 A - 1000 V rating with a breaking capacity of 15 kA and, on the other hand, a conventional spark gap (ignition voltage selected at 250 V) and a standard (sand) standard auxiliary fuse cartridge 100 A - 1000 V with a breaking capacity of 50 kA: the breaking time recorded is around 6 milliseconds.
Selon une variante d'exécution illustrée aux figures 4 et 5, le circuit 15 d'assistance à la coupure est simplement constitué par une varistance 59, de structure classique, en oxyde de zinc par exemple, qui est directement connectée entre les deux couteaux 48 et 49 de la cartouche fusible principale 12. La varistance 59 est conçue en fonction du courant de court- circuit présumé à couper et elle constitue en soi un élément électronique qui, monté en parallèle sur la cartouche fusible, remplit à lui seul la double fonction d'être nor a- lement isolant, mais susceptible de devenir conducteur à partir d'une tension de seuil donnée appliquée à ses bornes, d'une part, et d'interrompre rapidement le courant de court- circuit, d'autre part.According to an alternative embodiment illustrated in FIGS. 4 and 5, the circuit 15 for cutting assistance is simply constituted by a varistor 59, of conventional structure, made of zinc oxide for example, which is directly connected between the two knives 48 and 49 from the main fuse cartridge 12. The varistor 59 is designed as a function of the presumed short-circuit current to be cut and it constitutes in itself an electronic element which, mounted in parallel on the fuse cartridge, alone fulfills the double function of being normally insulating, but likely to become conductive from a given threshold voltage applied to its terminals, on the one hand, and to quickly interrupt the short-circuit current, on the other hand.
Sur la figure 6, on a montré l'allure de la tension V appli¬ quée aux bornes de la varistance 59 en fonction du courant I, ladite varistance étant de forte valeur tant que sa tension de seuil Vs' n'est p cas atteinte.In FIG. 6, the shape of the voltage V applied to the terminals of the varistor 59 has been shown as a function of the current I, said varistor being of high value as long as its threshold voltage Vs' is not c reached.
De manière à permettre l'interruption du courant passant dans la varistance, comme on le verra plus loin, la tension de seuil V ' est déterminée à partir de la formule classique suivante :In order to allow the interruption of the current passing through the varistor, as will be seen below, the threshold voltage V 'is determined from the following conventional formula:
' VR - V = RI + L §§ ' V R - V = RI + L §§
SOit (VR - RI) - V = LLet (V R - RI) - V = L
avec VR : tension du réseau V : tension d'arcwith V R : network voltage V: arc voltage
I : courantI: current
R : résistance du circuitR: circuit resistance
L : inductance du circuitL: circuit inductance
D'après cette formule, on voit que pour une tension d'arc VAccording to this formula, we see that for an arc voltage V
(appliquée aux bornes de la varistance) supérieure à une tension de seuil V ' égale à VR au terme RI près, le terme -3-r est négatif, de sorte que le courant I passant dans la varistance, comme le montre la figure 6, décroît puis s'annule.(applied to the terminals of the varistor) greater than a threshold voltage V 'equal to V R at the term RI close, the term -3-r is negative, so that the current I passing through the varistor, as shown in the figure 6, decreases then cancels.
En référence aux figures 4 à 6, le fonctionnement est le suivant. Tout d'abord, dans des conditions normales de fonctionnement du circuit, figure 4, le courant permanent parcourant la ligne dans le sens indiqué par la flèche passe presque intégralement dans la cartouche fusible 12 qui ne fonctionne pas, la varistance 59 étant de forte valeur pour la très faible tension qui apparaît aux bornes de la cartouche.With reference to FIGS. 4 to 6, the operation is as follows. First of all, under normal operating conditions of the circuit, FIG. 4, the permanent current flowing through the line in the direction indicated by the arrow passes almost entirely through the fuse cartridge 12 which does not work, the varistor 59 being of high value for the very low voltage that appears across the cartridge.
Lorsqu'il apparaît comme précédemment un court-circuit d'intensité élevée supérieure au propre pouvoir de coupure de la cartouche fusible 12, celle-ci fonctionne selon le principe que l'on a déjà exposé. Ainsi, au cours du fonc¬ tionnement de la cartouche 12, la tension d'arc V qui se développe à ses bornes, donc qui apparaît aux bornes de la varistance 59, croît très rapidement pour atteindre, par exemple au point P sur la figure 6, une valeur supérieure à la tension de seuil V ', de sorte que le courant de court- circuit I passe en totalité dans le chemin dérivé que constitue la varistance 59 (figure 5) . * Dès lors, le terme - Γ dans la formule indiquée ci-dessus devenant négatif, le courant I (figure 6) décroît puis s'annule rapidement -r la coupure du court-circuit est réali¬ sée.When a short circuit of high intensity appears above as above the own breaking capacity of the fuse cartridge 12, the latter operates according to the principle which has already been explained. Thus, during the operation of the cartridge 12, the arc voltage V which develops at its terminals, therefore which appears at the terminals of the varistor 59, increases very rapidly to reach, for example at point P in the figure 6, a value greater than the threshold voltage V ′, so that the short-circuit current I passes entirely through the derivative path that constitutes the varistor 59 (FIG. 5). * Consequently, the term - Γ in the formula indicated above becoming negative, the current I (figure 6) decreases then is canceled quickly - r the cut of the short circuit is realized.
On indiquera qu'à titre de sécurité vis-à-vis d'éventuels courants de fuite produits par la varistance, la cartouche fusible peut être équipée d'un organe appelé percuteur (non figuré) qui est adapté pour provoquer, dès le fonctionnement de la cartouche, l'ouverture d'un microcontact classique agencé en sortie de la varistance.It should be noted that, as a safety measure against possible leakage currents produced by the varistor, the fuse cartridge can be equipped with a member called striker (not shown) which is adapted to cause, as soon as the the cartridge, the opening of a conventional microswitch arranged at the outlet of the varistor.
On a donc réalisé suivant l'invention une cartouche fusible dont le propre pouvoir de coupure est artificiellement augmenté par adjonction d'un circuit d'assistance à la coupure, lequel est d'une structure particulièrement simple et peu coûteuse. On notera que la description ci-dessus a été faite en réfé¬ rence à une cartouche fusible principale réalisée selon une version à pistons ; bien sûr, l'invention s'applique égale¬ ment à toute autre structure de cartouche fusible qui garan- tit un isolement total lors de son fonctionnement. A fuse cartridge has therefore been produced according to the invention, the own breaking capacity of which is artificially increased by adding a breaking assistance circuit, which is of a particularly simple and inexpensive structure. It will be noted that the above description has been made with reference to a main fuse cartridge produced according to a piston version; of course, the invention also applies to any other structure of a fusible cartridge which guarantees total isolation during its operation.

Claims

Revendications claims
1. Dispositif d'interruption de courant pour la protection d'un circuit électrique contre un court-circuit, comportant une cartouche fusible (12) dite principale, caractérisé en ce que la cartouche fusible principale (12) a un pouvoir de coupure inférieur au courant de court-circuit présumé à couper et renferme des moyens (23, 24) aptes à établir une distance d'isolement suffisante pour empêcher tout réamorçage d'un arc électrique, et que le dispositif comporte également, en parallèle sur la cartouche fusible principale, un circuit (15) d'assistance à la coupure du courant de court-circuit, lequel comprend :1. Current interruption device for the protection of an electrical circuit against a short circuit, comprising a so-called main fuse cartridge (12), characterized in that the main fuse cartridge (12) has a breaking capacity lower than short-circuit current presumed to be cut and contains means (23, 24) capable of establishing a sufficient isolation distance to prevent any re-ignition of an electric arc, and which the device also comprises, in parallel on the main fuse cartridge , a circuit (15) for assisting in breaking the short-circuit current, which comprises:
- un élément (56 ; 59) normalement isolant, mais susceptible de devenir conducteur à partir d'une tension de seuil donnée appliquée à ses bornes de manière à dériver la totalité du courant de court-circuit immédiatement après le début du fonctionnement de la cartouche fusible princi¬ pale ; et- an element (56; 59) normally insulating, but capable of becoming conductive from a given threshold voltage applied to its terminals so as to derive the entire short-circuit current immediately after the start of operation of the cartridge main fuse; and
- des moyens (57 ; 59) aptes à interrompre le courant pas- sant dans ledit élément.- Means (57; 59) capable of interrupting the current passing through said element.
2. Dispositif selon la revendication 1, caractérisé en ce que ledit élément est constitué par un éclateur (56) conçu de manière à fonctionner à la tension de seuil, laquelle est choisie inférieure à la tension d'arc maximale apparaissant aux bornes de la cartouche fusible principale (12) lors de son fonctionnement, et que les moyens d'interruption du courant sont constitués par une cartouche fusible standard (57) dite auxiliaire, montée en série avec l'éclateur, du type faible calibre comparative¬ ment à la cartouche fusible principale, c'est-à-dire de valeur de courant nominal nettement inférieure et de même valeur de tension nominale, et ayant un pouvoir de coupure au moins égal au courant de court-circuit présumé à couper. 2. Device according to claim 1, characterized in that said element consists of a spark gap (56) designed so as to operate at the threshold voltage, which is chosen to be less than the maximum arc voltage appearing across the cartridge main fuse (12) during its operation, and the current interruption means consist of a standard fuse cartridge (57) called auxiliary, mounted in series with the spark gap, of the low caliber type compared to the cartridge main fuse, that is to say with a significantly lower nominal current value and the same nominal voltage value, and having a breaking capacity at least equal to the short-circuit current presumed to be cut.
3. Dispositif selon la revendication 2, caractérisé en ce que la cartouche fusible auxiliaire (57) est du type cylindrique ou à couteaux, avec un remplissage de sable.3. Device according to claim 2, characterized in that the auxiliary fuse cartridge (57) is of the cylindrical or knife type, with a filling of sand.
4. Dispositif selon la revendication 1, caractérisé en ce que ledit élément et les moyens d'inter¬ ruption du courant sont constitués par une seule et même varistance (59) conçue en fonction du courant de court- circuit à couper, la tension de seuil appliquée à ses bornes étant choisie supérieure à la tension nominale de la cartou¬ che fusible principale (12) mais inférieure à la tension d'arc maximale apparaissant aux bornes de la cartouche fusible principale (12) lors de son fonctionnement.4. Device according to Claim 1, characterized in that the said element and the means for interrupting the current consist of a single varistor (59) designed as a function of the short-circuit current to be cut, the voltage of threshold applied to its terminals being chosen greater than the nominal voltage of the main fuse cartridge (12) but less than the maximum arc voltage appearing at the terminals of the main fuse cartridge (12) during its operation.
5. Dispositif selon la revendication 1, caractérisé en ce que les moyens (23, 24) aptes à établir une distance d'isolement suffisante sont constitués par au moins un piston propulsable par l'énergie de l'arc électri- que. 5. Device according to claim 1, characterized in that the means (23, 24) capable of establishing a sufficient isolation distance consist of at least one piston propellable by the energy of the electric arc.
PCT/FR1987/000243 1986-06-25 1987-06-24 Fuse device for breaking a current WO1988000390A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8609180A FR2586858B1 (en) 1986-06-25 1986-06-25 FUSE CURRENT INTERRUPTION DEVICE
FR86/09180 1986-06-25

Publications (1)

Publication Number Publication Date
WO1988000390A1 true WO1988000390A1 (en) 1988-01-14

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ID=9336688

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FR1987/000243 WO1988000390A1 (en) 1986-06-25 1987-06-24 Fuse device for breaking a current

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FR (1) FR2586858B1 (en)
WO (1) WO1988000390A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0713607B1 (en) * 1993-07-12 2000-03-15 The University Of Sydney Fuse arrangement
AU687418B2 (en) * 1993-07-12 1998-02-26 University Of Sydney, The Fuse arrangement

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE263435C (en) *
FR888827A (en) * 1940-08-24 1943-12-23 Oerlikon Maschf High voltage fuse circuit breaker
DE829187C (en) * 1948-10-02 1952-01-24 Siemens Schuckertwerke A G Arrangement for switching off overcurrents in high-voltage systems
US4008452A (en) * 1975-08-01 1977-02-15 Westinghouse Electric Corporation Current limiting fuse device for relatively high current
DE2537252A1 (en) * 1975-08-21 1977-02-24 Siemens Ag Overcurrent and short circuit protection - has insulating protrusion of specified dimensions next to fuse with passage for gases
US4528536A (en) * 1984-01-09 1985-07-09 Westinghouse Electric Corp. High voltage fuse with controlled arc voltage
US4528537A (en) * 1984-01-09 1985-07-09 Westinghouse Electric Corp. High current zinc oxide fuse

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE263435C (en) *
FR888827A (en) * 1940-08-24 1943-12-23 Oerlikon Maschf High voltage fuse circuit breaker
DE829187C (en) * 1948-10-02 1952-01-24 Siemens Schuckertwerke A G Arrangement for switching off overcurrents in high-voltage systems
US4008452A (en) * 1975-08-01 1977-02-15 Westinghouse Electric Corporation Current limiting fuse device for relatively high current
DE2537252A1 (en) * 1975-08-21 1977-02-24 Siemens Ag Overcurrent and short circuit protection - has insulating protrusion of specified dimensions next to fuse with passage for gases
US4528536A (en) * 1984-01-09 1985-07-09 Westinghouse Electric Corp. High voltage fuse with controlled arc voltage
US4528537A (en) * 1984-01-09 1985-07-09 Westinghouse Electric Corp. High current zinc oxide fuse

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Publication number Publication date
FR2586858A1 (en) 1987-03-06
FR2586858B1 (en) 1993-05-07

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