Patent Publication Number: US-10763060-B2

Title: Mechanical cut-off apparatus for a high-voltage or very high-voltage electric circuit with splitting device

Description:
FIELD 
     The disclosure relates to the technological field of breaker apparatuses for high voltage electric circuits. 
     BACKGROUND 
     In conventional manner, electricity networks on the scale of a region, of a country, or of a continent, in which electric currents are transported over several tens, hundreds, or thousands of kilometers, are high voltage alternating current (AC) networks. Nowadays, trends in such networks are towards interconnecting infrastructures so as to obtain networks that are meshed, i.e. networks having a plurality of available paths between any two given points of the network. Furthermore, proposals have been made to develop networks or network portions using very high voltage direct current (DC), possibly integrated within meshed networks, together with portions of AC networks. 
     One of the problems in meshed networks lies in the possibility of transferring load currents between the different branches of the network in order to reorganize power flows, with this requiring electric circuits under high voltage to be opened or closed. This problem is even more acute with DC circuits. A conventional approach would be to use circuit breakers as breaker apparatuses, given that they are designed in particular to make it possible to open an electric circuit under load in which they are interposed. Nevertheless, circuit breakers are apparatuses that are complex, expensive, and voluminous, and they are intended for network protection functions, and would be under-used in such circumstances. In order to perform such load transfer functions, it may be helpful to use apparatuses of simpler design, such as disconnectors, even though those apparatuses are not primarily designed to break circuits that are under load. In the usual way in order to provide safety for equipment and personnel during interventions, disconnectors are to be found at each end of a line. It is thus appropriate to extract maximum benefit from those apparatuses. 
     In particular for high voltage circuits, it is also known to use so-called “metal-clad” apparatuses in which active breaker members are enclosed in a sealed enclosure filled with an insulating fluid. Such a fluid may be a gas, commonly sulfur hexafluoride (SF 6 ), but it is also possible to use liquids or oils. The fluid is selected for its insulating character, in particular so as to present dielectric strength that is greater than that of dry air at equivalent pressure. Metal-clad apparatuses may be designed in particular so as to be more compact than apparatuses in which breaking and insulation are provided using air. 
     A conventional disconnector comprises in particular two electrodes that are held by insulating supports in stationary positions that are spaced apart from the peripheral wall of an enclosure, which wall is at ground potential. The electrodes are connected together electrically or separated electrically as a function of the position of a movable connection member forming part of one of the electrodes, e.g. a sliding tube actuated by a control. The tube is generally carried by one electrode, to which it is electrically connected, and separating the tube from the opposite electrode is likely to create an electric arc that may lengthen during the opening movement of the disconnector, while the tube is moving away from the opposite electrode. Conventionally, the disconnector has two pairs of electrical contacts carried by the tube and the two electrodes. The first pair is the pair that passes the nominal current in the fully closed position of the apparatus. This path for passing current, referred to as the “nominal path”, presents a path of least electrical resistance, thereby reducing conduction losses under steady conditions. This pair of contacts is associated with a second pair referred to as “arcing” contacts or as the secondary contact pair. The two contacts in this pair are caused to remain in close contact while the first pair is separated so as to avoid any arcing phenomenon on the first pair and thereby guarantee a good state of electrical conduction in the fully closed position. Conversely, the contacts of the secondary pair separate later on and an electric arc is struck between them. They need to be able to withstand such wear. Once the electric arc becomes long enough, and after a sufficient length of time, the electric arc becomes interrupted. 
     A disconnector is generally situated in an electricity substation. It is connected to the other elements of the substation, e.g. by busbars. On either side of a disconnector, other elements of the substation may be found such as a circuit breaker, a power transformer, an overhead bushing, . . . . 
     Such a disconnector without any specific device for facilitating breaking could be used to transfer those currents, and it would be capable of accommodating smaller stresses, but it would be inappropriate for circuits that present large loop impedances. 
     Under such circumstances, opening can lead to electric arcs that may stretch to considerable lengths, and that can lead to various problems. An arc that is too long between the connection member and the opposite electrode can degenerate and turn into a short circuit. For example, in a disconnector of the above-described type, an arc might strike between the live electrode and the wall of the enclosure connected to ground. In a less extreme situation, arc extinction times can become too long and can damage component parts and thus endanger the insulation of the system. 
     In certain circuit breakers designed to operate with AC at medium voltage, an arc splitter chamber is provided that is separate from the zone in which the movable connection member moves and that is offset away therefrom. An electric arc that forms, e.g. during opening of the circuit, is split into a multiplicity of arcs. Such circuit breakers require means to be provided for causing the arc to move away from the zone in which the movable member moves and towards the splitter chamber, e.g. by using a magnetic field, which may be created by permanent magnets or which may be induced by current flowing in a magnetic circuit. Either way, this aspect is complex to manage and requires numerous round trips during design stages in order to ensure that the arc goes into the splitter chamber, since the way the system behaves varies as a function of the magnitudes of the currents being switched. Furthermore, the splitter chamber constitutes additional bulk. For a metal-clad apparatus, this volume also needs to be insulated from the tank at ground potential in order to guarantee electrical insulation. This can lead to tanks of large size and costs that are disadvantageous. 
     SUMMARY 
     There therefore remains a need to create apparatus for breaking high voltage circuits that is compact and capable of opening a circuit that is passing its nominal load current, and to do so under conditions that do not affect either the safety or the lifetime of the apparatus, while taking account in particular of regulatory constraints. 
     To this end, the disclosure provides mechanical breaker apparatus for a high voltage or very high voltage electric circuit, the apparatus being of the type comprising two electrodes that are to be connected electrically respectively to an upstream portion and to a downstream portion of the electric circuit, the two electrodes of the mechanical apparatus being movable relative to each other in an opening movement between at least one electrically open position and at least one electrically closed position in which they make a nominal electrical connection of the apparatus, said nominal electrical connection serving to pass a nominal electric current through the apparatus, and the apparatus being of the type including an electric arc splitter device having a multitude of distinct conductive elements that, for at least one active state of the splitter device, are spaced apart and electrically insulated from one another so as to define, in a surrounding insulating fluid, a multitude of successive distinct individual free paths in which electric arcs can be struck on opening and/or closing the electric circuit. 
     According to embodiments of the disclosure, the apparatus is characterized in that the splitter device comprises a first portion and a second portion, at least one of which is movable relative to the other with a relative spacing movement between: 
     at least one electrical contact position of the two portions defining a continuous electrically-conductive path for the nominal electric current through the apparatus; and 
     at least one spaced-apart position of the two portions; 
     and in that the splitter device includes at least one series of distinct conductive elements that are arranged along the continuous electrically-conductive path as defined by the two portions of the splitter device in the electrical contact position for passing the nominal electric current through the apparatus. 
     According to embodiments of the disclosure, which may be combined with the features but which may also be independent therefrom, the above-defined apparatus is characterized in that the splitter device comprises a first portion and a second portion, at least one of which is movable relative to the other with a relative spacing movement between: 
     at least one electrical contact position of the two portions; and 
     at least one spaced-apart position of the two portions; 
     in that one of the two relatively movable portions of the splitter device includes an elongate contactor, the contactor being electrically connected, at least during a stage of breaking the contact, with one of the portions of the electric circuit, and the other of the two relatively movable portions of the splitter device includes an insulating body having arranged thereon said series of distinct conductive elements; and
 
in that the contactor and the series of distinct conductive elements are arranged respectively in such a manner that in the electric contact position of the two portions, the distinct conductive elements are arranged on the insulating body in succession along the elongate contactor.
 
     In a third aspect of the disclosure, which may be combined with the first but which is independent therefrom, the above-defined apparatus is characterized in that the splitter device comprises a first portion and a second portion, at least one of which is movable relative to the other with a relative spacing movement between: 
     at least one electrical contact position of the two portions; and 
     at least one spaced-apart position of the two portions; 
     in that each of the two relatively movable portions of the splitter device includes an insulating body having arranged thereon a series of distinct conductive elements that are electrically insulated from one another; and 
     in that the two series of distinct conductive elements are arranged respectively in such a manner that: 
     in the electrical contact relative position of the two portions, each distinct conductive element of the two series, with the exception of end elements, is electrically in contact with two successive distinct conductive elements of the other series; and 
     in at least one spaced-apart relative position, and in any spaced-apart relative position of the two portions distinct from the electrical contact relative position of the two portions, each distinct conductive element of the two series may be spaced apart from distinct conductive elements of the other series. 
     According to optional characteristics of embodiments of the disclosure, taken singly or in combination, and in association with any of the aspects of embodiments of the disclosure: 
     in the electrically closed position of the electrodes of the mechanical apparatus, the nominal electric current flows along a main continuous electrically-conductive path, and the continuous electrically-conductive path for the nominal electric current defined by the two portions of the splitter device in the electrical contact position constitutes a secondary continuous electrically-conductive path through the apparatus, along which said distinct conductive elements are arranged; 
     in the electrically closed position of the electrodes of the mechanical apparatus, the nominal electric current flows along the continuous electrically-conductive path for the nominal electric current defined by the two portions of the splitter device in the contact position, which constitutes a main continuous electrically-conductive path through the apparatus along which said distinct conductive elements are arranged; 
     at least one of the portions of the splitter device includes said series of distinct conductive elements arranged along the continuous electrically-conductive path; 
     for said spaced-apart position of its two portions, the splitter device defines a desired electrical path between the upstream portion and the downstream portion of the electric circuit, which desired electrical path comprises in alternation conductive sections comprising the distinct conductive elements, and insulating sections comprising the successive distinct individual free paths; 
     for said spaced-apart position, the sum of the lengths of the distinct individual free paths of the desired electrical path is greater than the length of the spacing movement of the two portions between their contact position and said spaced-apart position; 
     in their contact position, the two portions of the splitter device are in electrical contact via a multitude of distinct electrical contacts, each of which involves at least one of the distinct conductive elements; and 
     the relative spacing movement of the two portions is controlled by the opening movement of the electrodes of the apparatus between their extreme open and closed positions. 
     According to optional characteristics of the disclosure, taken singly or in combination, and in association with other embodiments of the disclosure: 
     that in the extreme spaced-apart position, the contactor is spaced apart from the distinct conductive elements; 
     the contactor is elongate along a helical curve; and 
     the insulating body on which the series of distinct conductive elements is arranged forms a channel in which the contactor extends in the contact position, the channel being released of the contactor at least in part in spaced-apart or intermediate positions so as to form a preferred electric arc path between two successive distinct conductive elements. 
     According to optional characteristics of embodiments of the disclosure, taken singly or in combination, and in association with the third aspect of the disclosure: 
     the relative spacing movement of the two portions of the splitter device causes the electrical contact between all of the distinct conductive elements of the two series to be made simultaneously or broken simultaneously; 
     in order to ensure contact at each of the intended contacts, means are provided to compensate for geometrical dispersions; 
     the distinct conductive elements of at least one of the two series are resilient; 
     in order to ensure contact at each of the intended contacts, resilient contact elements are interposed; 
     in the spaced-apart position, distinct individual free paths are created firstly between a distinct conductive element of a first series and a proximal distinct conductive element of the other series, and secondly between said proximal distinct conductive element of the other series and another distinct conductive element of the first series; 
     insulating obstacles are provided to limit the appearance of electric arcs between two adjacent distinct conductive elements of a given series; 
     for each of the portions of the splitter device, the distinct conductive elements of a given series are arranged on the insulating body in a helical arrangement, and the two helices of the two portions are coaxial and interleaved; 
     for each of the portions of the splitter device, the distinct conductive elements of a given series are arranged on the insulating body in a plurality of parallel rows, and the rows of the two portions are parallel and interleaved; and 
     in the electrical contact position of the two portions of the splitter device, a nominal load current through the connection apparatus passes via the distinct conductive elements of the splitter device. 
     According to optional characteristics of embodiments of the disclosure, taken singly or in combination, and in association with any of the aspects of the disclosure: 
     a first of the two electrodes is stationary and a second of the two electrodes includes a movable connection member; 
     a first portion of the splitter device is carried by the first electrode; a second of the two portions of the splitter device is carried by the first portion of the splitter device or by the first electrode, with the possibility of relative spacing movement between the contact position and the spaced-apart position; the movable connection member is in contact with the second portion of the splitter device between a closed position of the movable connection member and an intermediate position of the movable connection member corresponding to the spaced-apart position of the two portions of the splitter device; and the movable connection member is spaced apart from the second portion of the splitter device between its intermediate position and an extreme open position; 
     between the closed and intermediate positions of the movable connection member, at least one distinct conductive element of the splitter device is electrically connected to the movable connection member by the movable connection member making contact with the second portion of the splitter device; 
     in the electrical contact position of the two portions of the splitter device, a nominal load current through the connection apparatus passes via electrical contact between the movable connection member and the second portion of the splitter device; 
     the apparatus includes a sealed enclosure enclosing an insulating fluid and in which there are arranged at least the first electrode and the second electrode, and at least some of the distinct conductive elements of the splitter device are housed in an internal cavity arranged in the first electrode or the second electrode; 
     the internal cavity is arranged inside an envelope determined by a conductive peripheral surface of the first electrode; 
     at least the second electrode includes a movable connection member that is movable along an opening movement relative to the first electrode between an extreme electrically open position and an extreme electrically closed position in which it makes a nominal electrical connection with the first electrode, and the internal cavity is arranged inside an envelope determined by a conductive peripheral surface of the movable connection member; 
     at least one of the portions of the splitter device is carried by the first electrode, and the relative spacing movement of the two portions is controlled by the opening movement of the electrodes between their extreme open and closed positions; 
     the preferred electrical path is superposed on the path of at least one of the two portions of the splitter device in its relative spacing movement; 
     in their relative contact position, the two portions of the splitter device make a continuous electrically-conductive path between the upstream portion and the downstream portion of the electric circuit; 
     the distinct individual free paths are arranged in series along the preferred electrical path; 
     two successive distinct individual free paths are electrically connected by one of the distinct conductive elements, each individual free path being defined between two proximal distinct conductive elements; 
     a distinct conductive element connects together no more than two distinct individual free paths; 
     at least some of the distinct individual free paths extend along a path that presents a non-zero component in projection in a direction perpendicular to the path of the opening movement of the electrodes; and 
     at least some of the distinct individual free paths extend with overlap in the direction of the relative spacing movement of the two portions of the device with at least one other distinct individual free path. 
     Various other characteristics appear from the following description made with reference to the accompanying drawings, which show embodiments of the disclosure as non-limiting examples. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a breaker apparatus of the type of the disclosure. 
         FIG. 2  is a section view of a first embodiment of a breaker apparatus according to embodiments of the disclosure. 
         FIG. 3  is an exploded perspective view showing a first embodiment of a splitter device for an apparatus according to embodiments of the disclosure. 
         FIGS. 4 to 7  are diagrammatic views in axial section for various relative positions of the components of the  FIG. 3  splitter device and of a movable connection member for an apparatus according to embodiments of the disclosure. 
         FIGS. 8 and 9  are diagrammatic views of a device of the type shown in  FIGS. 4 to 7 , in section on a plane containing the axial direction, showing respectively the positions of  FIGS. 4 and 7 . 
         FIG. 10  is a cutaway diagrammatic perspective view of a portion of the  FIG. 3  splitter device. 
         FIG. 11  is an exploded perspective view showing a second embodiment of a splitter device for an apparatus according to embodiments of the disclosure. 
         FIGS. 12 and 13  are perspective views showing respectively first and second portions of the  FIG. 11  splitter device. 
         FIG. 14  is a perspective view, partially in section, showing the  FIG. 11  splitter device when assembled. 
         FIGS. 15 and 16  are diagrams showing the respective positions of distinct conductor elements of the two portions of the  FIG. 11  device in developed views rolled-out flat. 
         FIG. 17  is an exploded perspective view showing a third embodiment of a splitter device for an apparatus according to embodiments of the disclosure. 
         FIGS. 18 to 20  are partially cutaway perspective views respectively showing three distinct relative positions of the two portions of the  FIG. 17  splitter device. 
         FIG. 21  is a partially cutaway diagrammatic perspective view showing a  FIG. 17  splitter device installed in a breaker apparatus. 
     
    
    
     DESCRIPTION 
       FIGS. 1 and 2  show the main component elements of a mechanical breaker apparatus according to embodiments of the disclosure for a high voltage or very high voltage electric circuit. 
     Such an apparatus is to open or close an electric circuit that may convey nominal currents, i.e. established currents for which the apparatus is designed to operate continuously without damage, at a voltage higher than 1000 V for AC or 1500 V for DC, or even under very high voltage, i.e. a voltage higher than 50,000 V for AC or 75,000 V for DC. 
     The apparatus is a mechanical breaker apparatus insofar as the electric circuit is opened by separating and moving apart two contact parts so as to interrupt the flow of current through the apparatus. The electric circuit may be closed by moving two contact parts until they come into contact so as to reestablish a flow of current through the apparatus. 
     In the embodiments described below, the mechanical breaker apparatus is a disconnector. Nevertheless, embodiments of the disclosure can be implemented in the context of a circuit breaker or of a switch. In the embodiments, the breaker apparatus is designed to break a single electric circuit, e.g. one phase, however embodiments of the disclosure can be implemented in apparatus that is designed to break a plurality of electric circuits, then comprising a plurality of breaker devices in parallel, e.g. within a common enclosure. 
     More particularly, the disclosure is described in the context of a breaker apparatus of the so-called “metal-clad” type. The apparatus  10  thus comprises an enclosure  12  defined by a peripheral wall  14 . The peripheral wall  14  defines an inside volume  16  of the enclosure  12  and is provided with a series of openings  18  that serve, at least for maintenance or assembly operations, to provide access to the inside volume  16  from outside the enclosure, or that enable the volume  16  to be put in communication with another volume of another enclosure placed next to the peripheral wall  14  around the opening. When the apparatus is in an operating configuration, the enclosure  12  may be leaktight relative to the outside of the peripheral wall  14 . The openings in the wall are thus designed to be closed, e.g. by inspection ports, or caps, or to put the inside volume  16  of the enclosure  12  into communication with another enclosure that is itself leaktight, by making the opening coincide with a corresponding opening of the other enclosure. By being leaktight in this way, the internal volume  16  of the enclosure  12  can be filled with an insulating fluid that can be separated from atmospheric air. The fluid may be a gas or a liquid. The pressure of the fluid may be different from atmospheric pressure, e.g. a pressure higher than 3 bars absolute, or the pressure may be very low, possibly close to a vacuum. The insulating fluid may be air, for example, air at a pressure that is higher than atmospheric pressure. Nevertheless, the fluid may be selected because of its highly insulating properties, e.g. having dielectric strength that is greater than that of dry air under equivalent conditions of temperature and pressure. 
     In general manner, the apparatus  10  has at least two electrodes that are to be connected electrically respectively to an upstream portion and to a downstream portion of the electric circuit that is to be broken, and that are movable relative to each other with an opening movement between at least one electrically open position, corresponding to an open state of the apparatus, and an electrically closed position in which they make a nominal electrical connection of the apparatus, thus corresponding to a closed state of the apparatus. In the present text, the opening movement may take place in an opening direction from the electrically closed position to the electrically open position, or in the closing direction from the electrically open position to the electrically closed position. In the example shown, the apparatus  10  includes in particular a stationary first electrode  20  and a second electrode  22  that comprises a stationary main body and a movable connection member  24 . 
     In the example shown, each electrode  20 ,  22  is fastened in the enclosure  12  by means of an insulating support  26 , represented in this example as being in the form of a bowl that is fastened to the peripheral wall  14  so as to close an opening  18  that is provided for this purpose, the electrode being arranged on an inside of the support  26 . On the outside of the support  26  relative to the inside volume  16 , the support  26  carries a connection terminal  28 ,  30  that is electrically connected to the corresponding electrode  20 ,  22 . The connection terminals  28 ,  30  are thus arranged outside the enclosure  12 . One of the terminals is for connecting to an upstream portion (not shown) of the electric circuit, while the other terminal is for connecting to a downstream portion (not shown) of the electric circuit. In arbitrary manner, and without this having any particular meaning concerning the polarity or the flow direction of the current, the portion referred to as the upstream portion of the electric circuit is the portion that is connected to the first electrode  20  via the connection terminal  28 . Consequently, the downstream portion of the electric circuit is the portion that is connected to the second electrode  22  via the connection terminal  30 . 
     Each electrode  20 ,  22  is electrically connected in permanent manner to the associated connection terminal  28 ,  30 , regardless of whether the breaker apparatus is in the open state or the closed state. 
     Each electrode  20 ,  22  has a stationary main body made of a conductive material, in particular a metal material, having an outer peripheral surface  32 ,  34  that is conductive and that presents a shape that is essentially convex without any projecting portions. As described below, each electrode  20 ,  22  presents an internal cavity  31 ,  33  contained inside the envelope defined by the conductive outer peripheral surface  32 ,  34  of the stationary main body. 
     In the example shown, the peripheral wall  14  presents a generally cylindrical shape about a central axis A 1 , and the two electrodes  20 ,  22  together with their associated terminals  28 ,  30  present elongate shapes, respectively along an axis A 2  and along an axis A 3 . In this example, the axes A 2  and A 3  are parallel. The axes A 2  and A 3  are perpendicular to the central axis A 1  of the wall  14  and they are offset from each other along the direction of the axis A 1 . In addition to being offset in this way along the direction of the central axis A 1 , the terminals  28  and  30  are arranged opposite from each other on either side of the central axis A 1 . 
     The main bodies of the two electrodes  20 ,  22  are arranged in stationary manner in the inside volume  16 , being spaced apart from the peripheral wall  14  of the enclosure  12  and being spaced apart from each other in such a manner that an inter-electrode electrical insulation space is arranged along the direction of the central axis A 1  between facing portions of their respective outer peripheral surfaces  32 ,  34 . 
     In the example shown, the movable connection member  24  of the second electrode of the apparatus comprises a sliding tube  36  of axis A 1  that is guided to slide along the central axis A 1 , which is arbitrarily referred to herein as being “longitudinal”, in a cylindrical internal cavity of axis A 1  in the stationary main body of the second electrode  22 . 
     The connection member  24  is movable in an opening movement relative to the opposite electrode  20  between an extreme electrically open position shown in  FIG. 2  and an extreme electrically closed position in which the electrical connection member  24  makes a nominal electrical connection with said opposite electrode  20 . In the example shown, the sliding tube  36  of the movable connection member  24  may be made of conductive material, e.g. of metal, and it is electrically connected to the main body of the second electrode, and thus electrically connected to the associated connection terminal  30  in permanent manner, regardless of the position of the movable connection member  24 . 
     In the example shown, when the connection member  24  is in its extreme open position, it is received entirely inside the corresponding cavity of the second electrode so as to minimize any risk of electric arcing. In its extreme closed position, the connection member  24  is moved longitudinally along the central axis A 1  towards the first electrode  20  through the inter-electrode electrical insulation space. In known manner, the connection member  24  is moved between these two extreme positions by a control mechanism  42  that, in the embodiment shown, comprises a connecting rod  44  that is movable in a direction substantially parallel to the axis A 1  and that is itself controlled by a rotary lever  46 . 
     In arbitrary manner, the longitudinal movement of the connection member  24  is said to be “forwards” when going from its extreme open position to its extreme closed position, i.e. from right to left in  FIG. 3 . Consequently, the opposite direction is arbitrarily referred to as “rearwards”. 
     It is known that a major problem with this kind of breaker apparatus is associated with electric arcs appearing while the circuit is being opened, and sometimes also while it is being closed, in particular if opening or closing is performed while the electric circuit is live and is conveying a large current. In order to handle this problem, the apparatus  10  of the disclosure includes an electric arc splitter device  48 . 
     In the embodiment shown in  FIG. 2 , the electric arc splitter device  48  may be contained at least in part and possibly for the most part, or even completely in the internal cavity of one of the electrodes, specifically in the first electrode  20 . By being arranged in this way inside the envelope determined by the conductive peripheral surface  32 , the electric arc splitter device can be integrated in the apparatus  10  without disturbing the electric fields that exist in the inside volume when the apparatus is in its closed state. As a result, there is no need to modify the design of the apparatus in order to continue complying with the dielectric strength of the apparatus. By housing the electric arc splitter device at least in part, and possibly for the most part, or even in full in the cavity of the electrode, a limit may be put on any need to enlarge the apparatus, in particular any need to enlarge the internal volume, which is favorable to ensuring the apparatus is compact. The shape of the tank can thus continue to be somewhat cylindrical, which may be desirable in terms of substation compactness. The splitter device may be received entirely inside the internal cavity. 
     The splitter device  48  may be housed inside the movable connection member  24 , or in a cavity of the main body of the second electrode  22 . The splitter device  48  could thus be received in a cavity formed inside an envelope determined by a conductive peripheral surface of the sliding tube  36 . 
     The operation of a first embodiment of a splitter device is described below with reference to  FIGS. 3 to 10 . 
       FIG. 3  shows the main components of a first embodiment of a splitter device  48  suitable for being used in the disclosure.  FIGS. 4 to 7  show various different relative positions of these components.  FIGS. 8 and 9  are diagrammatic plan views for a contact position and for a spaced-apart position of the device. 
     The first embodiment comprises a first portion  50  and a second portion  52  that are movable relative to each other with relative spacing movement, in this example along the direction of the central axis A 1  between at least one electrical contact position, shown in  FIGS. 4, 5, and 8 , and a position in which the two portions are spaced apart, shown in  FIGS. 6, 7, and 9 . In this example, the relative spacing movement is movement in pure translation along the axis A 1 . 
     In the embodiment of the breaker apparatus that is described, the splitter device is arranged in the apparatus so that: 
     in an extreme closed position of the movable connection member  24 , corresponding to the electrically closed position of the electrodes of the mechanical apparatus, the nominal electric current, or at least a large portion thereof, flows along a main continuous electrically-conductive path, specifically directly between the movable connection member  24  and the main body of the first electrode  20 , without this majority of the nominal current passing via the splitter device  48 . As can be seen in  FIG. 4 , the nominal current, or at least a majority thereof, flows via a pair of main contacts that are formed in this example by the front end  25  of the sliding tube  36  of the movable connection member  24  and by a contact surface  21  of the main body of the first electrode  20 . 
     In contrast, for positions of the movable connection member  24  lying between the extreme closed position shown in  FIG. 4  and a position shown in  FIG. 5 , and for which contact between the pair of main contacts is lost, a secondary continuous electrically-conductive path is defined for the nominal electric current through the apparatus. This secondary continuous electrically-conductive path is defined through the splitter device  48 , so long as the two portions of the splitter device are still in their electrical contact relative position. 
     In this embodiment, each of the two portions  50 ,  52  has an insulating body with a series of distinct conductive elements arranged thereon that are electrically insulated from one another, where a “series” contains a plurality of distinct conductive elements. As can be seen below: 
     in the contact position of the two portions  50 ,  52 , each conductive element of the two series, with the exception of the end elements, is in electrical contact with two successive distinct conductive elements of the other series; and 
     in any spaced-apart position of the two portions, distinct from the electrical contact position of the two portions, each conductive element of two series is spaced apart from the distinct conductive elements of the other series. 
     In  FIG. 3 , it can be understood that the first portion comprises a carriage carrying a plurality of bars  54  that extend in the transverse direction and that are made of insulating material, in which there is arranged a first series of distinct conductive elements  53 , as can be seen in  FIGS. 8, 9, and 10 , which elements may for example be in the form of U-shaped jumpers. 
     By way of example, the bars  54  are carried by a U-shaped frame  55  that extends in a plane containing the central axis A 1  and the transverse direction of the bars  54 , the frame  55  being open towards the rear, specifically towards the second electrode  22 . The insulating bars  54  are in the form of rectangular parallelepipeds that extend in the transverse direction and that have respective rearwardly-facing faces  83  with recesses  84 . The bars  54  form an insulating body for the first portion  50  of the device. 
     The insulating body for the first portion  50  of the device may be made at least in part out of one or more insulating materials so as to provide electrical insulation between two adjacent distinct conductive elements of the same portion. The insulation that is obtained may prevent any dielectric breakdown or any movement of the electric arc in the material of the insulating body between the two adjacent distinct conductive elements during a stage of interrupting an arc, in particular. By way of example, the insulating body is made on the basis of polytetrafluoroethylene (PTFE), and/or on the basis of perfluoroalkoxy (PFA), and/or on the basis of polyoxymethylene (POM). In addition to their insulating character, such materials may present a strong ablation character enabling electric arcs to be cooled effectively and thus increasing voltage across their terminals, thereby having the effect of enhancing the extinction process. The main material constituting the bars  54  may present dielectric strength greater than 5 kilovolts per millimeter (kV/mm), and, for example, good resistance to the wear caused by an electric arc. 
     Jumpers  53  of conductive material are embedded in the insulating bars  54  so that each of the two ends of a jumper  53  is flush outside the insulating bar in one of the recesses  84  in the rear face of the bar  54  in order to form an electrical contact  81 . In the example shown, each jumper  53  thus presents a transverse base portion that is embedded in the bar  54  and two parallel portions extending axially rearwards and having free ends outside the material of the bar  54  in the recesses  84  so as to form the electrical contacts  81 , as can be seen in  FIG. 10 . The recesses  84  are also open in bottom faces of the bars. In the example shown, the bars  54  are adjacent to one another in the direction of the axis A 1 , but the depth of the recesses  84  in this direction leaves space between the electrical contacts  81  of the jumpers and the front face of the immediately adjacent bar  54 . Each bar  54  has a plurality of jumpers  53  arranged side by side in the transverse direction. Because of the multiplicity of bars  54 , the jumpers  53  are thus arranged in parallel rows. 
     In the disclosure, the distinct conductive elements are made out of metal, for example. Their conductive character means that they present resistivity of less than 10 −6  ohm-meters (Ω·m). 
     In the example shown, each bar  54  includes single studs  57  on either side of the row of jumpers  53 , each stud having a base portion embedded in the bar  54  and a rear portion that extends axially rearwards with its free end outside the material of the bar  54  in a recess  84  so as to form an electrical contact  81  analogous to the electrical contacts of the jumpers  53  and in alignment therewith. In this embodiment, for the set of bars, provision is made for a first single stud  57 , carried by a bar  54 , specifically the bar arranged at the front along the axis A 1 , to form a front main terminal  61  that is to be electrically connected to a portion of the electric circuit that is to be broken. In this embodiment, the front main terminal  61  is permanently connected to the associated connection terminal  28 , and thus to the upstream portion of the electric circuit. In this embodiment, a second of these single studs  57 , carried by a bar  54 , specifically the bar arranged at the rear along the axis A 1 , forms a rear main terminal  63  that is for being electrically connected to the other one of the portions of the electric circuit that is to be broken. It is explained below that this electrical connection is effective only for certain positions of the movable connection member. 
     The other single studs are for electrically connecting together in pairs, one single stud  57  on one bar  54  being electrically connected to another single stud  57  situated, e.g. on the same transverse side, on one of the bars that is immediately adjacent, e.g. by a conductive bridge  65 . The set of two single studs  57  that are connected together by a single conductive bridge  65  thus forms the equivalent of a jumper having two electrical contacts, and thus forms a conductive element that is distinct in the meaning of the disclosure. 
     The second portion  52  of the splitter device  48  also has a carriage that is mechanically connected to the carriage of the first portion by a slideway connection  72 , thus ensuring that the two portions of the device can move relative to each other. By way of example, in the embodiment shown, each of the transverse ends of the bars  54  is provided with a cylindrical bore of axis A 1  so as to enable the bars to be mounted on two parallel rods of axis A 1  belonging to the second portion  52  in order to form the slideway connection between the two portions  50  and  52 . 
     The carriage of the second portion may have a base plate  74 , for example, made of insulating material, that extends in a plane parallel to the axis A 1  and to the transverse direction. The second portion  52  carries a series of distinct conductive elements, embodied in this example in the form of forks  76  having two branches  78  of conductive material extending vertically upwards from the base plate  74 , i.e. in a direction that is substantially perpendicular to the direction of the axis A 1  and to the transverse direction. As can be seen in  FIG. 10 , the two branches  78  of each fork  76  are connected together by a conductive bottom cross-member  80  whereby each fork  76  is fastened on the top face of the base plate  74 . The top free end portion of each branch  78  forms an electrical contact  82  that is to co-operate with a respective one of the electrical contacts  81  of the jumpers  53  of the first portion  50 . The forks  76  of the second portion  52  are also arranged in parallel transverse rows, each row corresponding to a row of jumpers  53  of the first portion. The electrical contacts  82  of the forks  76  may be made in material continuity with the remainder of the forks, or they may be in the form of fitted elements. If they are fitted elements, the electrical contacts  82  may be made of a conductive material that is different from the materials used for the remainder of the forks  76 , and in particular of a material that withstands electric arcs well. They may thus be made on the basis of tungsten or cupro-tungsten, while the remainder or the fork is then made on the basis of copper, for example. 
     As can be seen in particular in  FIGS. 8 to 10 , the two portions  50  and  52  are arranged relative to each other in such a manner that each branch  78  of a fork  76  is engaged in a recess  84  vertically from the bottom in such a manner that, in the direction of the axis A 1 , an electrical contact  82  of each branch  78  of the fork  76  faces an electrical contact  81  of a jumper  53  of the first portion. It can thus be observed that the base plate  74  of the second portion  52  is arranged below the insulating bars  54 . It can thus be seen, e.g. in  FIG. 9 , that for each of the portions  50 ,  52  of the splitter device, the distinct conductive elements of a given series are arranged on the insulating body  54 ,  74  of the corresponding portion in a plurality of parallel rows, and that the rows of the two portions are parallel and interleaved, in the sense that a row of elements of one series, and thus belonging to one portion of the splitter device, is arranged between two rows of elements of the other series, and thus belonging to the other portion of the splitter device. 
     It can be seen in  FIG. 10  that the recesses  84  possess a dimension in the direction of the axis A 1  that makes it possible, by relative axial movement of the two portions  50  and  52  of the splitter device, for there to be an electrical contact position as shown in  FIGS. 4, 5, and 8 , and a spaced-apart position without electrical contact as shown in  FIGS. 6, 7, and 9 . The relative movement, as determined in this example by the slideway, is movement in pure translation along the axis A 1 . 
     This embodiment of the disclosure thus has two distinct series of distinct conductive elements, one carried by the first portion and the other carried by the second portion. For at least one active state of the splitter device, corresponding in this example to a spaced-apart position of the two portions of the device, the distinct conductive elements are spaced apart and electrically insulated from one another so as to define within the surrounding insulating fluid a multitude of successive distinct individual free paths CLE in which electric arcs can be struck on opening and/or closing the electric circuit. Each individual free path CLE is an empty space in the surrounding insulating fluid between two distinct conductive elements, i.e. a path without any solid obstacle, in particular without any insulating solid obstacle. 
     For a spaced-apart position of its two portions, the splitter device  48  defines a preferred electrical path between the upstream portion and the downstream portion of the electric circuit, which preferred electrical path comprises conductive sections comprising the distinct conductive elements, specifically the jumpers  53  and the forks  76 , alternating with and insulating sections comprising the successive distinct individual free paths. 
     The successive distinct individual free paths CLE are considered to be sections that are insulating insofar as they correspond to a space in a fluid that, in the absence of an electric arc, may present greater insulation than dry air, as defined above. In the presence of an electric arc, the distinct individual free paths may lose their insulating character. 
     Nevertheless, it should be observed that the jumpers  53  are offset transversely relative to the forks such that, when the two portions  50  and  52  are in a contact position, each fork  76  is designed to come into contact via its two contacts  82  with two contacts  81  that belong to two adjacent jumpers in the corresponding row. Thus, in the contact position, a fork  76  makes an electrical connection between two adjacent jumpers  53 . One of these adjacent jumpers may have two single studs  57  connected together by a conductive bridge  65 , with one fork being in contact with one of the studs and another fork, belonging to another row being in contact with the other one of the studs. 
     In this embodiment, in the spaced-apart position, the distinct individual free paths are created firstly between a jumper  53  of the first series and a proximal fork  76  of the other series, as carried by the second portion  52 , and secondly between said proximal fork  76  and another jumper  53  of the first series. 
     In this first embodiment, the splitter device  48  has a contactor  39  that is arranged at the rear end of the device and that is thus carried by the carriage of the second portion of the splitter device. The contactor  39  is designed to be in contact with the connection member  24  when the apparatus is in its closed state, and more particularly in this example with a contactor  38  of the connection member  24 . In contrast, when the connection member  24  has reached an open position, the electrical contact between the contactor  38  of the movable connection  24  and the contactor  39  is broken. The contactor  39  is electrically connected to one of the distinct elements of the splitter device  48 , more precisely to the element that acts as the rear main terminal  63 . In this first embodiment, the contactor  39  is electrically connected to the rear terminal  63 , which is carried by the first portion of the splitter device  48 . 
     The first embodiment device of the disclosure also has an end-of-stroke absorber mechanism for absorbing the end of the stroke of the movable connection member so as to ensure an intermediate state of the breaker apparatus between the nominal closed state corresponding to the extreme position of the movable connection member  24 , as shown in  FIG. 4 , and a secondary closed state of the apparatus corresponding to the position shown in  FIG. 5 . 
     To do this, the end-of-stroke absorber mechanism enables the two portions  50  and  52  of the splitter device  48  to move together in the movement direction of the movable connection member  24 , specifically in this example in the direction of the axis A 1 , from a first contact position between the two portions as shown in  FIG. 5  to an offset position as shown in  FIG. 4 . 
     In the position of  FIG. 4 , the movable connection member  24  is in direct contact with the body of the electrode via the contact surface  21 . The contact may be radial contact between a cylindrical portion of the front end  25  of the sliding tube  36  and the contact surface  21  so as to guarantee electrical contact even in the event of position dispersion along the direction of the axis A 1 . In this state of the apparatus, the nominal electric current, or at least a major portion thereof, flows along a main continuous electrically-conductive path, specifically directly between the movable connection member  24  and the main body of the first electrode  20 . 
     On moving towards the rear, towards the position shown in  FIG. 5 , the front end  25  of the sliding tube  36  loses contact with the contact surface  21 . Nevertheless, up to the position of  FIG. 5 , it can be seen that a secondary continuous electrically-conductive path is defined for the nominal electric current through the apparatus. This secondary continuous electrically-conductive path is defined through the splitter device  48  so long as the two portions of the splitter device are still in their electrical contact relative position. For all of the positions between the position of  FIG. 4  and the position of  FIG. 5 , the contactor  38  of the movable connection member is in contact with the contactor  39  carried by the first electrode  20  in order to establish the secondary continuous electrically-conductive path through the splitter device having its two portions in an electrical contact position. 
     To do this, the transverse base of the U-shaped frame  55 , belonging to the first portion  50 , is secured to a guide assembly  56  that extends rearwards from the U-shaped base. The guide assembly  56  is received so as to be capable of sliding longitudinally inside a socket  58 , which is cylindrical in this example and which is designed to be fastened in the internal cavity  31  of the first electrode  20 . By way of example, the socket  58  presents a tubular body of axis A 1  with its front portion presenting a fastener flange  62  for fastening to the main body of the first electrode  20 , and with its rear portion presenting an inwardly-directed radial flange  64  that is to form a longitudinally rear abutment for the guide assembly  56 . The socket  58  is thus stationary in the mechanical breaker apparatus. The guide assembly  56 , and with it the entire first portion  50  of the splitter device, is designed specifically to slide along the longitudinal direction of the axis A 1  inside the socket  58  between an offset advanced position shown in  FIG. 4  and a retracted position shown in  FIG. 5 , in which the guide assembly  56  is longitudinally in abutment rearwards against the inwardly-directed radial flange  64  of the socket  58 . The guide assembly  56  is urged resiliently along the longitudinal direction towards its retracted position, e.g. by a helical spring  66  that is held inside the socket  58  by a front closure plate  68 , the spring  66  thus being compressed along the axis A 1  between the closure plate  68  and the guide assembly  56 . An index finger  70  is fastened to the guide assembly  56  so as to project radially outwards relative to an outer cylindrical wall of the guide assembly  56  and be received in a longitudinal groove of the tubular body of the socket  58  in order to index the first portion  50  angularly. 
     The various operational positions of the splitter system  48  are described below with reference to  FIGS. 4 to 7 . 
       FIG. 7  corresponds to an extreme open position of the connection member  24 . This position corresponds to the position of the connection member  24  that makes it possible to obtain the breaking capacity desired for the apparatus and the nominal insulation distance for the expected service conditions of the apparatus. It generally corresponds to the most retracted position of the connection member  24  allowed by the control mechanism  42  shown in  FIG. 2 . In this position of the connection member  24 , the splitter device  48  is subjected solely to the force of the spring  66 , which thus urges the first portion  50  towards its retracted position as shown in  FIGS. 5 to 7 . In this open state of the apparatus, the second portion  52  of the splitter device  48 , which in this embodiment is carried by the first portion  50 , is urged by a resilient member, e.g. a spring  90 , towards a position that is spaced apart from the first portion, specifically retracted rearwards along the direction of the axis A 1 . By way of example, this spaced-apart position is defined by a mechanical abutment acting between the two portions  50  and  52  in the direction of their relative movement. In this relative position of the two portions, there is no electrical contact between the two portions  50  and  52 , in particular no electrical contact between the distinct conductive elements of the first portion, i.e. the jumpers  53 , and the distinct conductive elements of the second portion, i.e. the forks  76 . It may be observed that there then exists a large distance between the contactor  39  of the splitter device, specifically carried by the second portion  52  at its rear end, and the contactor  38  of the connection member  24 . 
     It can be understood that this state of the apparatus corresponds to its open state in which no electrical connection is made through the apparatus between the upstream and downstream portions of the electric circuit, at least under nominal operating conditions of the apparatus. 
     By moving the connection member  24  with its opening movement, in this example in the direction for closing the electric circuit, the intermediate position shown in  FIG. 6  is reached, which corresponds to the position in which the first contact is made between the contactor  38  of the connection member  24  and the contactor  39  of the splitter device  48 . In this position, there is still no movement of the two portions of the splitter device relative to each other, so they are still in their relatively spaced-apart position, nor is there any movement of the splitter device  48  as a whole relative to the socket  58 , and thus relative to the first electrode  20 . For this intermediate position of the connection member  24 , in which electrical contact is made between the connection member  24  and the splitter device  48 , the breaker apparatus is still in an electrically open state. There is no direct electrical contact between the upstream and downstream portions of the electric circuit for breaking. In contrast, it may be that the capacity of the breaker apparatus for providing electrical insulation in this position or in a position that is intermediate between the positions of  FIG. 6  and of  FIG. 5 , i.e. the maximum voltage that it may be necessary to withstand between the upstream and downstream portions of the electric circuit without electric arcs forming, is less than its capacity for electrical insulation corresponding to the extreme open position of the connection member  24 . Specifically, in this state, the rear end terminal  63  of the splitter device is taken to the potential of the downstream portion of the electric circuit via the movable connection member  24  and the contactors  38  and  39 . 
     By continuing to move the connection member  24  in its opening movement, still in the direction for closing the electric circuit, the position shown in  FIG. 5  is reached, which corresponds to the position in which the two portions  50  and  52  of the splitter device are in the electrical contact position. In this position, all electrical contacts between the distinct conductive elements of one portion and the distinct conductive elements of the other portion are made and effective. Thus, the contacts  82  of the forks  76  are bearing against the contacts  81  of the jumpers  53  so as to provide electrical contact between the various distinct conductive elements. It should also be observed that in this position, as can be seen in  FIG. 8 , a front end fork  76 V is in contact with the front main terminal  61 , and a rear end fork  76 R is in electrical contact with the rear main terminal  63 . In the example shown, the front and rear main terminals  61  and  63  are formed by single studs  57  carried by the first portion of the device. Nevertheless, the two terminals could be carried by the second portion of the device, or it would also be possible to provide for one main terminal to be carried by the first portion and the other main terminal to be carried by the second portion. 
     For this relative contact position of the two portions  50  and  52 , provision may be made for it to correspond not to a first contact position between the various distinct conductive elements  76 ,  53 , but rather for it to correspond to a relative position of the two portions beyond a first contact position towards the front in the direction of relative movement between the two portions. This is made possible in this embodiment by the fact that the contacts  82  of the forks  76  are arranged at the free ends of the branches  78  of the U-shaped forks  76 , which branches  78  extend perpendicularly to the direction of relative movement between the two portions, and can deform elastically in order to absorb the movement of the base plate  74  of the second portion, which carries the bases of the forks  76 , beyond a first contact position. This imparts sufficient pressure between the two contacting parts  81 ,  82  to allow current to flow without damage during the time needed for setting up the nominal current along the secondary continuous electrically-conductive path. A result of the same kind could be obtained by making provision for the jumpers  53  to be mounted in the bars  54  with an ability to move in the direction of relative movement between the two portions, for example by being urged resiliently towards a retracted position towards the rear along the axis A 1 . The electrical contact position as shown in particular in  FIG. 5  and in  FIG. 8  may be determined by mechanical abutments between the two portions of the splitter device  48 , preventing these two portions for continuing their relative movement towards each other. 
     Starting from this relative position of the various components of the apparatus, as shown in  FIG. 5 , the breaker apparatus is in an electrically closed state in which a secondary electrical connection of the apparatus is set up. In this position, a nominal electric current can flow through the breaker apparatus  10 . This nominal electric current flows along the secondary continuous electrically-conductive circuit through the splitter device prior to flowing along the main continuous electrical conductive circuit once the pair of main electrical contacts  21 ,  25  have come into contact, as shown in  FIG. 4 . 
     It should thus be observed that the movement of the connection member  24  towards its extreme closed position shown in  FIG. 4 , continues towards the front from the position shown in  FIG. 5 . This movement is made possible in particular by the end-of-stroke absorber mechanism, with the two portions of the splitter device  48  thus moving together in the movement direction of the connection member, specifically by the guide assembly  56  of the first portion  50  sliding in the socket  58 . The two portions of the splitter device may remain in their electrical contact relative position. 
     In this embodiment, it should thus be observed that between the positions of  FIGS. 4 and 5 , so long as the pair of main contacts  21  and  25  are not in contact, a nominal load current passes through the breaker apparatus with the two portions  50  and  52  of the splitter device  48  in electrical contact via the distinct conductive elements  76 ,  53  of the splitter device  48 , which elements are arranged along the secondary continuous electrically-conductive circuit. With reference to  FIG. 8  and assuming that the front main terminal  57  of the splitter device is electrically connected in permanent manner to the upstream portion of the electric circuit that is to be broken, in particular by the main body of the first electrode  20  and by the connection terminal  28 , it can be understood that the electric current is then conveyed by direct conduction from the front end terminal  57  towards a first jumper  53  of the first portion by the front end fork  76 V. This first jumper  53  conveys the current to a second fork  76  adjacent to the first via their respective facing contacts, and the second fork conveys the current to a second jumper  53  adjacent to the first jumper, via their respective facing contacts. This current conduction continues through the various successive distinct conductive elements, given that the two series of distinct conductive elements are interleaved relative to each other along the continuous electrically-conductive path, such that the nominal electric current flows by passing in alternation from a distinct conductive element of one series carried by one portion of the splitter device to a distinct conductive element of the other series carried by the other portion of the splitter device. 
     Thus, in their contact relative position, the distinct conductive elements  53 ,  76  forming parts respectively of the two portions  50  and  52  of the splitter device make, by being put into contact, an electrically-conductive path between the upstream portion and the downstream portion of the electric circuit, which path is continuous, i.e. without any interruption to electrical conduction through a conductive solid medium. In the absence of contact between the main contacts  21 ,  25 , this continuous electrically-conductive path is a path of least electrical resistance between the upstream portion and the downstream portion of the electric circuit for the contact position of the members of the apparatus. The distinct conductive elements are arranged in series along the continuous electrically-conductive path. 
     There follows a description of a step of opening the electric circuit, possibly performed under load, while the nominal current is flowing through the apparatus. 
     In the state of  FIG. 4 , the apparatus simultaneously presents both the main continuous electrically-conductive path directly from the main body of the stationary electrode  20  to the movable connection member  24  via the main contacts  21  and  25 , and also the secondary continuous electrically-conductive path. Nevertheless, the main continuous electrically-conductive path may present lower resistance, such that a majority of the nominal current through the apparatus flows along the main continuous electrically-conductive path rather than along the secondary continuous electrically-conductive path. 
     Starting from the state described with reference to  FIG. 4 , the movable connection member  24  is controlled to retract. Until reaching the position of  FIG. 5 , the entire splitter device  48  retracts with the connection member  24  insofar as the guide assembly  56  of the first portion  50  of the device  48  is free to slide relative to the socket  58 . During this movement, the nominal electric current flows through the breaker apparatus. Nevertheless, this nominal electric current is transferred from the main continuous electrically-conductive path to the secondary continuous electrically-conductive path through the splitter device  48 , as a result of the main continuous electrically-conductive path being broken by loss of contact between the main contacts  21  and  25 . Nevertheless, since both continuous electrically-conductive paths were already made, this transfer takes place without any risk of an electric arc being created. 
     On reaching the position of  FIG. 5 , corresponding to a first intermediate position of the movable connection member  24 , the guide assembly  56  comes into abutment against the radial flange  64  of the socket  58 , preventing any subsequent rearward movement of the first portion  50  of the device  48 . In this state, the nominal current can still flow along the secondary continuous electrically-conductive path through the splitter device  48 . 
     When the movable connection member  24  continues its rearward opening movement, in the opening direction, beyond the position of  FIG. 5 , the spring  90  that is arranged between the two portions of the splitter device pushes the second portion  52  of the device  48  so as to keep it pressed via its contactor  39  against the contactor  38  of the movable connection member. The two portions  50  and  52  thus move apart from each other along their spacing movement, and the contacts between the forks  76  and the jumpers  53 , i.e. the electrical contacts between the two portions  50  and  52  of the device are broken simultaneously, ignoring geometrical dispersions. In this state, it can thus be seen that at each of the contacts  81 ,  82  of the forks  76  with the jumpers  53 , respective distinct individual free paths CLE are created simultaneously corresponding to the empty spaces in the insulating fluid that are created between the pairs of contacts  81 ,  82  as a result of the two portions  50  and  52  moving relatively apart from each other. For the position shown in  FIG. 5 , it can be considered that each distinct individual free path CLE is of zero length since the two portions are in the contact position, and that the length of each individual free path increases progressively starting from this zero value and simultaneously for all of the individual free paths, in proportion to the spacing apart of the two portions  50  and  52  of the splitter device  48  from the electrical contact position towards at least one spaced-apart position of the two portions. 
     In the position that follows immediately after losing contact, this length of the individual free paths is so small that electric arcs are struck in each of the individual free paths CLE. In the presence of these electric arcs, current flows through the breaker apparatus  10  and through the splitter device  48 . As a result of the way the system is configured, the electric arcs that appear in the individual free paths are connected in series along the flow path of the current. Specifically, the current is then constrained to flow along the preferred electrical path that comprises in alternation conductive sections constituted by the distinct conductive elements, namely the jumpers  53  and the forks  76 , and “insulating” sections made up of the successive distinct individual free paths. Once more, it should be understood that in the presence of an arc, an individual free path CLE has lost its insulating character, but can recover it as soon as the arc is extinguished. 
     In each distinct individual free path, the electric arc in the individual path creates an arc voltage that opposes the voltage across the electrical apparatus between the upstream and downstream portions of the electric circuit that is to be broken. In known manner, this arc voltage has a value that can be written in the following form (to a first approximation and for a constant current):
 
 U  arc =Uo+k□l   CLE  
 
     where: 
     Uo is a constant, generally of the order of 10 V to 25 V; 
     k is a multiplicative factor that may be considered as being constant; and 
     l CLE  is a value that represents the length of the individual free path, i.e. a value representative of the distance in the position under consideration between the contact  81  of a jumper  53  and the facing contact  82  of a fork  76 . 
     In this embodiment, it can be understood that by creating a multitude of individual free paths simultaneously in the preferred electrical path through the splitter device  48 , an arc voltage is created in each individual free path that opposes the passage of the current, with these arc voltages adding together since the individual free paths are in series along the preferred electrical path. Thus, for a splitter device that simultaneously creates N individual free paths (which in the example shown assumes (N/2)−1 distinct conductive elements in the first series and N/2 distinct conductive elements in the second series, plus the front and rear end terminals), a total arc voltage is created immediately along the preferred electrical path that is not less than N□Uo. 
     It can also be understood that as the two portions of the splitter device  48  move further apart, the k□l CLE  term for the arc voltage in each arc increases in proportion to the spacing between the two portions, and for the splitter device as a whole this portion of the total arc voltage increases with the factor N representing the number of individual free paths, and thus very quickly. 
     In this first embodiment, the first series of distinct conductive elements as carried by the first portion  50  comprises four rows of three jumpers  53 , each row lying between a single stud  57  at each transverse end. The second series of distinct conductive elements, as carried by the second portion  50 , comprises four rows of four forks  76 . On opening, the splitter device  48  thus forms simultaneously thirty-two distinct individual free paths CLE in series along the preferred electrical path. 
     Thus, in this embodiment, even with small relative spacing between the two portions of the splitter device, and thus even for small relative movement between the two electrodes in their opening movement, a total arc voltage is created that quickly becomes large and that is of a value that increases very quickly with relative movement between the two electrodes. 
     Furthermore, because the splitter device  48  is arranged inside a cavity  31  of one of the electrodes, the electric arcs are confined inside the electrode and present little risk of degenerating by going to the wall  14  of the enclosure. 
     When the system reaches the position of  FIG. 6 , the total arc voltage through the splitter device  48  may have reached a value such that it causes the electric arc to disappear. In the position shown in  FIG. 6 , the second portion  52  of the device  48  has reached its position of maximum spacing relative to the first portion  50  and can no longer retract towards the second electrode  22 . 
     Under all circumstances, when the movable connection member  24  continues its retraction movement from the position of  FIG. 6  towards the position of  FIG. 7 , the contactor  38  of the connection member  24  loses contact with the contactor  39  of the splitter device  48 , and moves progressively away therefrom. If an electric current is still present at the moment contact is lost (assuming that the electric arcs in the splitter device are not yet extinguished) then an electric arc may be created between the two contactors  38  and  39  in the same manner as in a conventional apparatus. Nevertheless, this arc between the two contactors  38  and  39 , which creates an additional arc voltage that adds to the total arc voltage inside the splitter device  48 , will normally lead quickly to the electric arcs in the apparatus being extinguished, with this happening at a relatively small value for the spacing between the two contactors  38  and  39 , which value is sufficiently small to avoid creating any risk of seeing the arc degenerate by going to the wall  14  of the apparatus. 
     A second embodiment of the disclosure is described below that makes use of the same operating principle, but merely with a different geometrical configuration for the distinct conductive elements. As in the first embodiment, this second embodiment presents two portions that are movable relative to each other between a contact position and a spaced-apart position. Each portion  50 ,  52  comprises an insulating body, the insulating body of each portion carrying a series of distinct conductive elements. As in the first embodiment, a multitude of distinct individual free paths are created simultaneously (ignoring geometrical dispersions) in series along a preferred electrical path through the splitter device, with the individual lengths of these electrical paths increasing simultaneously and in proportion to the movement apart between the two portions of the device. 
     As can be seen more particularly in  FIG. 12 , the first portion  50  comprises an insulating body  92  that is tubular, in this example about the axis A 1 , and that has primary contact plates  94  of conductive material plugged into it, each plate forming a distinct conductive element of the first portion  50 . Each primary plate  94  extends radially inwards towards the axis A 1  from an inside cylindrical wall  96  of the tubular insulating body  92 . Each primary plate  94  presents the shape of an angular sector of an annulus of axis A 1  that extends angularly about the axis A 1 , e.g. in the range 5° to 30°, for example, in the range 10° to 20°, and that extends radially relative to the axis A 1  from the inside cylindrical wall  96  to an inner diameter of the plates  94 . Each primary plate  94  thus presents a front face and a rear face that are substantially plane and that lie in planes that are perpendicular to the axis A 1 . 
     The primary plates  94  may be all identical in shape. As can be seen in  FIGS. 11 and 12 , the primary plates  94  are received in corresponding housings  95  formed in the insulating body  92  and they are arranged in a helical configuration. Thus, two successive primary plates  94  are longitudinally offset in the direction of the axis A 1 . The axial offset D between two adjacent plates, e.g. as measured between the respective rear faces of two adjacent primary plates, may lie in the range 0.5 millimeters (mm) to 20 mm, for example, and for example, in the range 1 mm to 5 mm. In this embodiment, two adjacent primary plates  94  are also offset angularly so as to present no facing portions in the axial direction. Between two adjacent primary plates, provision may be made for example for a primary angular gap S 1  about the axis A 1 , this angular gap S 1  being measured between facing edges, one of which belongs to one of the plates and the other to the following plate, this angular gap S 1  may lie in the range 0.5° to 30°, and for example, in the range 5° to 20°. Thus, in projection along the direction of the axis A 1 , two adjacent primary plates  94  do not overlap. In the embodiment shown, and looking at the set of primary plates  94  along the direction of the axis A 1  from the rear end of the splitter device  48 , two adjacent primary plates  94  are arranged in such a manner that the primary plate  94  that is offset angularly clockwise from the other primary plate is also offset axially forwards relative to that other primary plate. With the exception of a front end primary plate  94 V and of a rear end primary plate  94 R, each primary plate  94  is thus located between two adjacent primary plates, which are the primary plates that are the closest to the primary plate  94  under consideration, both angularly and axially, and the three plates are considered as being successive in the first series of plates. In the example shown, the front end plate  94 V is designed to form a front end terminal that is to be electrically connected, for example, in a permanent manner, to a portion of the electric circuit that is to be broken, e.g. an upstream portion. 
     In the example shown, each turn of the helix on which the primary plates  94  are arranged has eight primary plates that are mutually spaced apart and electrically insulated from one another. In this example, provision is made for the helix to have eight turns, giving sixty-four primary plates  94 . 
     In the example shown, the first portion  50  of the splitter device  48  also has an outer envelope  97  that is made in the form of a tubular part of axis A 1 , for example made out of electrically insulating material, e.g. out of PTFE. The inside diameter of the tubular outer envelope  97  may be substantially equal to the outside diameter of the insulating body  92  of the first portion  50  so that it can be received when fitted with its primary plate  94  inside the outer envelope  97 . At its front axial end, the outer envelope  97  presents a radial flange enabling it to be connected to an annular guide assembly  56  that, as in the first embodiment, is designed to be slidably received along the axis A 1  in a socket  58  so as to form an end-of-stroke absorber mechanism for the connection member  24 , and as described with reference to the first embodiment. 
     The second portion  52  of the splitter device  48 , visible in  FIG. 13 , comprises an insulating body  98 , specifically a cylindrical body about the axis A 1  and having an outside diameter that is selected to allow the insulating body  98  to slide along the axis A 1  at the center of the set of primary plates  94  of the first portion  50 , for example, without making contact. This cylindrical insulating body  98 , which may be tubular or solid, carries a series of secondary contact plates  102  projecting radially outwards from its cylindrical outside peripheral surface  100 , thereby forming a corresponding number of distinct conductive elements of the second portion  52 . 
     Each secondary plate  102  is thus anchored in the insulating body  100 . Each secondary plate  102  extends radially outwards from an outside cylindrical surface of the cylindrical insulating body  98 . Each secondary plate  102  is generally in the form of an angular sector of an annulus about the axis A 1  and possesses an angular extent around the axis A 1  that lies for example in the range 5° to 30°, and possibly in the range 10° to 20°, and a radial extent along the axis A 1  from the outside cylindrical surface  100 . In this embodiment, each of the secondary plates  102  presents a front face that is substantially plane and contained in a plane perpendicular to the axis A 1 . 
     In the example shown, each of the secondary plates  102  presents a rear face presenting two contact elements that are offset along the direction of the axis A 1 . In this example, the contact elements are constituted by two surface elements  104  and  106 , each of which is substantially plane and contained in a respective plane perpendicular to the axis A 1 , the two planes of the two contact elements  104  and  106  being axially offset by an axial offset value D that is equal to the axial offset D between two adjacent primary plates  94  of the first series. Specifically, in an electrical contact relative position of the two portions, and possibly ignoring the end plates of the two series, a secondary plate  102  of the second portion is to come into contact simultaneously with two adjacent primary plates  94  of the first portion, and likewise a primary plate  94  of the first series is to come into contact simultaneously with two adjacent secondary plates  102  of the second portion. The surface elements  104  and  106  may be made of a conductive material that is different from the conductive material of a main body of the secondary plate, possibly a material that is better at withstanding electric arcs. 
     In analogous manner corresponding to the arrangement of the primary plates  94  of the first portion  50 , the secondary plates  102  are arranged in a helix. Thus, two adjacent secondary plates  102  are angularly offset relative to each other by an angular gap S 2  about the axis A 1  and they are axially offset by an axial offset D along the direction of the axis A 1 . The angular extent of a plate in one of the series may be greater than the angular gap between two adjacent plates of the other series with which the plate is to come into contact. 
     In the example shown, each turn of the helix in which the secondary plates  102  are arranged comprises eight secondary plates that are mutually spaced apart and electrically insulated from each other on the insulating body  98 . In this example, provision is made for the helix to have eight turns, giving sixty-four secondary plates  102 . 
     As can be seen in  FIG. 14 , the second portion  52  is received coaxially inside the tubular body  92  of the first portion  50 , and thus inside the outer envelope  97 . At its rear end, the outer envelope presents an annular transverse wall that is pierced in its center by an orifice  106  to allow the rear end of the insulating cylindrical body  98  of the second portion to pass while sliding axially along the axis A 1 . As can be seen in  FIG. 13 , this rear end of the insulating cylindrical body  98  carries a contactor  39  that is to come into electrical contact with the contactor  38  of the connection member  24 , as explained in the context of the first embodiment. By way of example, in this second embodiment, the contactor  39  may be electrically connected to a rear end secondary plate  102 R of the series of secondary plates  102  of the second portion, which forms a rear end terminal for the splitter device  48 . 
     With the splitter device  48  assembled in this way, for each of the portions  50 ,  52  of the splitter device, the distinct conductive elements  94 ,  102  in a given series are arranged on the insulating body carrying them in a helical configuration, and the two helices of the two portions share a common axis and are interleaved. For assembly purposes, provision may be made for the primary plates  94  to be plugged into the corresponding housings  95  in the insulating tubular body  92  of the first portion radially from the outside towards the inside after the first portion  50  carrying its secondary plates  102  has been engaged coaxially in the center of the insulating tubular body  92 . 
     The two portions  50  and  52  of the splitter device  48  can slide relative to each other in a spacing movement between a contact position shown in  FIG. 15  and a spaced-apart position shown in  FIG. 16 . In this example, the relative spacing movement between the two portions  50  and  52  is a movement in pure translation along the axis A 1 . 
     As in the first embodiment, a resilient return member, e.g. a spring between the two moving portions of the splitter device  48 , is provided so that in the absence of contact with the moving connection member  24 , the two portions occupy their spaced-apart relative positions. As can be seen more particularly in  FIG. 16 , in this spaced-apart position, all of the distinct conductive elements, specifically the primary plates  94  and the secondary plates  102 , are spaced apart from one another in the axial direction of the spacing movement of the two portions, preventing any electrical connection through a solid material between these distinct conductive elements. Under the effect of the movement of the connection member  24 , as described with reference to  FIGS. 6 and 7  for the first embodiment, the two portions of the splitter device can be moved into a contact position in which each of the plates in one series is connected to two plates of the other series in order to create an electrical connection through the splitter device that is solid, in the sense of continuity between electrically connected-together solid conductors, and as shown in  FIG. 15 . 
     To ensure contact at each of the contacts that are provided, provision may be made for means to compensate geometrical dispersions, e.g. by providing that the plates in at least one of the two series are resilient, or by interposing resilient contact elements. 
     In similar manner to the first embodiment, the splitter device  48  in this second embodiment can be integrated within the cavity  31  of the first electrode, or indeed in another variant in a cavity in the connection member  24 . Likewise, the breaker apparatus fitted with this second embodiment of a splitter device  48  can occupy the four states that are shown in  FIGS. 4 to 7  for the first embodiment, depending on the position of the connection member  24 . 
     In these first and second embodiments, in the electrical contact position between the two portions of the splitter device, the distinct conductive elements, specifically the two series, are electrically connected to the electric circuit and even form a portion of the electric circuit in that they are not only at the potential of that circuit, but in reality they also pass the nominal electric current, or in any event they are capable of passing this nominal electric current in the event that the apparatus includes a main continuous electrically-conductive path in the extreme closed position of the movable connection member, and a secondary continuous electrically-conductive path through the splitter device when the movable connection member has begun to move away from its extreme closed position. 
     Furthermore, it can be understood that in these embodiments, the electric arc splitter device comprises distinct conductive elements that, for at least one active state of the splitter device corresponding in both embodiments to the spaced-apart relative position of the two portions of the device, are spaced apart and electrically insulated from one another so as to define a multitude of successive distinct individual free paths in the surrounding insulating fluid, which paths may have electric arcs struck therein when the electric circuit is opened and/or closed. The distinct individual free paths are paths of reduced dielectric strength in the insulating fluid between two proximal distinct conductive elements belonging one to a series carried by one portion and the other to the other series carried by the other portion, along which paths electric arcs can be struck on opening and/or closing the electric circuit. It is along these individual free paths that there is a dielectric breakdown beyond a voltage difference threshold between the two proximal distinct conductive elements. 
     For these first and second embodiments of the disclosure, an individual free path in the spaced-apart position of the two portions of the device is provided between a distinct conductive element of one series carried by one of the portions and a distinct conductive element of the other series carried by the other one of the portions. In the first embodiment, such an individual free path CLE is provided between each contact  81  of a jumper  53  and the facing contact  82  of a branch  78  of a fork  76 . In the second embodiment, such an individual free path is provided, in the spaced-apart position of the two portions of the device, between the rear face of a primary plate  94  and one of the two surface elements  104 ,  106  of a secondary plate  102  through the surrounding fluid. 
     In both embodiments, two successive distinct individual free paths are electrically connected together by one of the distinct conductive elements, and each individual free path is defined between two proximal distinct conductive elements. In the first and second embodiments, two proximal distinct conductive elements do not belong to the same series, with one of them being carried by one of the portions and the other being carried by the other portion of the device. 
     Furthermore, a distinct conductive element may connect together at most two distinct individual free paths. 
     In the first embodiment, provision may be made for insulating solid obstacles to limit the appearance of electric arcs between two adjacent distinct conductive elements in the same series, i.e. in particular between two contacts  81  of two adjacent jumpers  53  on the same bar  54 , or between two contacts  82  belonging to two adjacent forks  76  in the same row. By way of example, these insulating obstacles are made in the form of insulating partitions  85  that extend rearwards from a rear face of a bar in order to define two recesses between them or to form two compartments within a single recess. 
     It can be understood that when the two portions of the splitter device are spaced apart, the splitter device is theoretically insulating between the upstream and downstream portions of the electric circuit that is to be broken. Nevertheless, this is only partially true insofar as, in the event of a very high potential difference existing between the upstream portion and the downstream portion, electric arcs can occur in the individual free paths that are created between the two portions of the splitter device, thus allowing current to flow through the splitter device, at least until the two portions are spaced apart by a certain amount. 
     In the splitter device of the disclosure, the distinct individual free paths are arranged successively in series along the preferred electrical path, thereby forming a corresponding number of relays in controlled positions for a series of electric arcs that might be struck. 
     It should be observed that at least some of these distinct individual free paths overlap with at least one other distinct individual free path in the direction of relative spacing movement between the two portions of the device. This makes it possible, in a given amount of space in the spacing direction between the two portions, to increase the number of arcs and/or to increase the total accumulated length of the distinct individual free paths, thereby ending up with an increased “arc length”, and thus an increased total arc voltage within the device. 
     In the first and second embodiments, it may be observed that although the splitter device is independent of the movable connection member (they are not mechanically connected together other than via stationary parts of the apparatus), the relative spacing movement between the two parts  50  and  52  is controlled by the opening movement of the electrodes of the apparatus between their extreme open and closed positions, specifically by the opening movement of the movable connection member  24 . In these two embodiments, one of the two relatively movable portions of the splitter device is carried by the other, and both portions are carried by only one of the two electrodes of the apparatus, specifically the stationary electrode  20 . 
     The overall size of the second embodiment of the splitter device  48  is substantially identical to the overall size of the first embodiment, thereby enabling it to be installed in a manner that is identical to that described above, e.g. inside the cavity  31  of the first electrode  20 . Nevertheless, it may be observed that the second embodiment of the disclosure, for given overall size, has a larger number of distinct individual free paths, specifically sixty-four. It may also be observed that the generally cylindrical shape of the second embodiment can make it easier to integrate in the arrangement that is generally used for such apparatuses. 
       FIGS. 17 to 21  show a third embodiment of the disclosure. 
     In the first two embodiments of the disclosure, the two relatively movable portions of the splitter device are carried one by the other, with one of the portions being secured to one of the electrodes of the breaker apparatus. The two relatively movable portions of the splitter device are thus distinct from the movable connection member that, under control from outside the enclosure of the apparatus, serves to cause the apparatus to open or close. 
     In the third embodiment of the disclosure, the splitter device has two portions  50  and  52 , however in this embodiment, one of the portions is secured to one of the electrodes, typically the first electrode  20 , while the second portion of the splitter device is secured to the movable connection member  24  that is carried by the other electrode. 
     Furthermore, unlike the first two embodiments in which each of the two relatively movable portions of the splitter device has a distinct series of distinct conductive elements, this third embodiment differs in that only one of the two relatively movable portions has a series of distinct conductive elements, while the other portion has one contactor. The series of distinct conductive elements may comprise a plurality of distinct conductive elements. 
     With reference to  FIG. 17 , it can be seen that the first portion  50  comprises at least a cylindrical insulating body that carries a series of distinct conductive elements laid out relative to one another on the insulating body along a layout curve. The distinct conductive elements are laid out in succession along this layout curve, for example, at regular intervals. This curve may be a rectilinear curve, i.e. a straight line, but it may be a curve that is not rectilinear, and that may be a non-rectilinear curve lying in a plane, but that may be a three-dimensional curve that cannot be inscribed in a plane. As explained below, this layout curve defines a preferred electrical path in an active state of the splitter device  48 . In the example described below, the layout curve is a helical curve of constant pitch. 
     The spacing between two successive distinct conductive elements along the layout curve for the successive distinct conductive elements may be smaller than the spacing between any other conductive elements that are not in succession along the layout curve. This makes it possible in particular to avoid an electric arc appearing between two distinct conductive elements that are not successive. In particular, for a helical curve, the pitch of the helix may be greater than this spacing. Nevertheless, other configurations may be used in order to avoid such unwanted arcs between two distinct conductive elements that are not in succession along the layout curve. 
     In the example shown in  FIGS. 17 to 21 , the insulating body of the first portion  50  is made up of two parts: an inner cylindrical part  110  of axis A 1 , and an outer tubular cylindrical part  112  of axis A 1 . Nevertheless, it should be observed that the disclosure can be implemented using only one of these two parts. In this embodiment, the distinct conductive elements are made in the form of plates  114  made at least in part out of conductive material. In this example, these plates  114  are substantially square in shape and each has a circular hole at its center. 
     In this embodiment with a two-part body, provision is made for each essentially plane plate  114  to be received in part in a corresponding housing  116  formed in the outside cylindrical surface  118  of the inner cylindrical part  110 , and in part in corresponding housings  120  arranged in an inside cylindrical surface  122  of the outer tubular cylindrical part  112 . More precisely, in this example, the housings  116  in the inner cylindrical part  110  are individual housings for each plate  114 . The plates  114  may be received in these housings  116  in the inner part  110  so as to be blocked in a desired orientation. In the example shown, this orientation corresponds to each plate being arranged in a radial plane containing the axis A 1  so as to project radially outwards from the outside cylindrical surface  118  of the inner cylindrical part  110 . A plurality of plates  114  may be contained in the same radial half-plane containing the axis A 1  and bounded by the axis A 1 , being offset relative to one another axially along the axial direction A 1  by a distance that is equal to the helical pitch of the layout curve. In the example shown, the housings  120  in the outer tubular cylindrical part  112  are made in the form of slots that are elongate in the axial direction A 1  and that open out into the inside cylindrical surface  122  of the outer tubular cylindrical part  112 . This configuration is favorable for assembly purposes since it is possible to place the plates  114  in their individual housings  116  in the inner part  110 , and then cause that assembly to slide axially inside the outer tubular cylindrical part  112 , with different aligned plates being received in a common slot  120 . An inverse configuration could be used, with the individual housings arranged in the outer part  112  and slots arranged in the inner part  110 . Likewise, the plates  114  could be fastened in only one of the inner or outer parts, without being received, not even in part, in a housing in the other one of the parts. 
     In an improvement, at least one of the two parts of the insulating body includes a groove that extends along the layout curve on which the plates  114  are arranged. The groove is for receiving a contactor  128  of the second portion  52  of the splitter device  48 , at least in an electrical contact relative position of the two portions of the splitter device. Specifically, this groove is thus a helically-shaped elongate groove. In the example shown, each of the two parts of the insulating body is provided with a respective groove. An inner groove  124  is arranged in the outside cylindrical surface  118  of the inner part  110 , and in section perpendicular to the helical layout curve of the plates it presents a section that is circularly arcuate, e.g. semicircular and radially open outwards in the outside cylindrical surface  118 . An outer groove  126  is arranged in the inside cylindrical surface  122  of the outer part  112 , and in section perpendicular to the helical layout curve of the plates  114  it presents a section that is circularly arcuate, e.g. semicircular, being radially open inwards in the inside cylindrical surface  122 . When the inner and outer parts  110  and  112  of the insulating body are assembled together, the inner and outer grooves  124  and  126  are arranged facing each other along the helical layout curve of the plates so as to form a channel in the insulating body, which channel is of substantially circular section and extends along the layout curve of the plates  114 . The plates  114  are mounted in the insulating body in such a manner that their central holes are concentric with the section of the channel formed by the inner and outer grooves  124  and  126  in the insulating body. 
       FIG. 17  also shows a front end plate  114 V that is carried by the insulating body and that is to form a front end terminal that is electrically connected to one of the portions of the electric circuit that is to be broken, specifically the upstream portion connected to the first electrode  20 . 
     The second portion  52  of the splitter device  48  essentially comprises a contactor  128  that is elongate along a layout curve identical to the layout curve of the plates  114  of the first portion  50 . The contactor  128  is made so as to be conductive over its length and it is designed to be carried at its front end by the movable connection member  24  via a fastener interface  130 . In the example shown, the fastener interface  130  is in the form of a cylindrical drum of axis A 1  that is mounted on the movable connection member  24  so as to be capable of turning about the axis A 1 . The turning of the drum  130  about the axis A 1  may be free or it may be controlled by the control mechanism  42 . The contactor  128  is cantilevered out forwards from the drum  130  so as to extend forwards freely. 
     The contactor  128  is electrically connected to the other of the two portions of the electric circuit that is to be broken, specifically the downstream portion that is connected to the second electrode  22 . 
     Movement of the movable connection member  24  to perform opening movement, in the opening direction or the closing direction for the electric circuit, and under the control of the control mechanism  42 , thus corresponds in this embodiment to moving both portions  50  and  52  of the splitter device  48 . 
       FIGS. 18, 19, and 20  show various configurations of this third embodiment of the splitter device  48  corresponding to different operating states. In these figures, the system is shown diagrammatically without showing the integration of the contactor  128  on the connection member  24 . 
       FIG. 18  shows an electrical contact position between the two portions  50  and  52  of the splitter device  48 . In this extended position, the contactor  128  is arranged so as to be received in the channel formed by the inner and outer helical grooves  124  and  126  of the insulating body. As a result, the contactor  128  is engaged in an interstitial space between the inner and outer parts  110  and  112  of the insulating body of the first portion. In this position, a free front end portion  129  of the contactor  128  is in electrical contact with the plates  114 V forming the front end terminal. As a result, the downstream portion of the electric circuit, which is electrically connected in permanent manner to the contactor  128 , is electrically connected by this electrical contact to the upstream portion of the electric circuit, thus allowing the nominal current to pass through the breaker apparatus, this nominal current flowing in the contactor  128 . The two portions of the splitter device thus set up a continuous electrically-conductive path between the upstream portion and the downstream portion of the electric circuit, in particular along the contactor  128 . 
     As for the first and second embodiments, provision may be made for the two portions of the splitter device when in the electrical contact relative position to make a secondary continuous electrically-conductive path that takes the place of a main continuous electrically-conductive path between the movable connection member  24  and the main body of the stationary electrode  20 , with this happening as soon as direct contact between the movable connection member  24  and the main body of the stationary electrode  20  is lost at a pair of main contacts. To do this, provision may be made for an end-of-stroke absorber mechanism as described for the above embodiments. Nevertheless, such an end-of-stroke absorber mechanism is not shown in  FIGS. 17 to 21 . 
     As a result, in this position that is obtained for an electrical closure position of the electrodes of the mechanical apparatus, all of the distinct conductive elements that form part of the series carried by the relatively movable first portion of the splitter device are arranged along the continuous electrically-conductive path. 
     Furthermore, with the configurations of the plates  114  extending across the channel defined by the grooves  114 ,  116 , the contactor  128  is also engaged through the central hole in each of the plates  114 . 
     In a desirable manner, the contactor  128  is then in electrical contact with each of the plates  114  along the layout curve of the plates. The contactor  128  may be provided with an outer conductive surface over its entire length corresponding to the length of the layout curve for the plates  114 . 
       FIG. 19  shows a relative position of the two portions of the splitter device  48  corresponding to an intermediate spaced-apart position. This position may correspond in particular to an intermediate position of the movable connection member. It can thus be seen that the contactor is retracted rewards relative to the position of  FIG. 18 . In this intermediate position, the contactor  128  is nevertheless still partially engaged in the channel defined along the layout curve of the plates  114  of the first portion, while nevertheless not extending over the entire length of the channel. Thus, the free end  129  of the contactor  128  is no longer in electrical contact with the end terminal  114 V. As a result, the solid conductive path between the upstream portion and the downstream portion of the electric circuit that is to be broken is interrupted. Depending on the intermediate position, the contactor  128  is also disengaged and spaced apart from a certain number of plates among the first plates  114  in their successive order from the front towards the rear along the layout curve of the plates. In this position, each of the plates of this group of plates  114  from which the contactor is disengaged is thus spaced apart from and electrically insulated relative to the other plates  114  and the contactor  128  (in the absence of any electric arc). In contrast, the contactor  128  remains engaged with the remaining plates, i.e. with the group of successive plates that are arranged behind the front free end  129  of the contactor along the layout curve of the plates, for the position under consideration of the contactor  128  relative to the insulating body  110 ,  112 . 
     The spacing movement of the contactor  128  relative to the plates  114  carried by the insulating body of the first portion  50  is movement in which the contactor  128  moves along the layout curve of the plates  114  over the insulating body. In the example shown, this movement is thus helical movement combining both movement in translation along the axis A 1  and movement in rotation about the axis A 1 , the two movements being proportional as determined by the pitch of the helix formed by the layout curve of the plates. The contactor extends along the same helix. In an embodiment in which the plates are arranged by way of example along a circularly arcuate curve contained in a plane, the contactor would be in the form of a circular arc having the same radius and the same center, and the movement would be relative movement in rotation about the center of the arc of a circle that is common both to the layout curve of the plates and to the contactor. 
     In the position of  FIG. 19 , all of the plates  114  situated in front of the front free end  129  of the contactor  128  are disengaged from the contactor. The portion of the channel along the layout curve of the plates that is situated between the front free end  129  of the contactor  128  and the front end terminal  114  is released from the contactor. Over this portion, there is thus a certain number of plates  114 , referred to as the “front group” of plates, that are separated by distinct individual free paths CLE that follow one another in series along the layout curve of the plates. 
     In this intermediate spaced-apart position, the splitter device  48  defines a preferred electrical path between the upstream portion and the downstream portion of the electric circuit, which path comprises, between the front main terminal  114 V and the front end of the contactor  128 , an alternation of conductive sections comprising the distinct conductive elements, specifically the distinct conductive elements of the front group of plates, all carried by the same relatively movable portion of the plate device, and insulating portions (in the absence of electric arcs) comprising the successive distinct individual free paths defined between successive pairs of plates  114  of the front group. In this embodiment, the individual free paths are created between distinct conductive elements  114  belonging to the same series, and carried by the same relatively movable portions  50  of the splitter device  48 . 
       FIG. 20  shows an extreme spaced-apart position for the two portions of the splitter device in which the contactor  128  is fully disengaged from the insulating body  110 ,  112  carrying the plates  114 . The front free end  129  of the contactor  128  is thus arranged at a distance from the rear end plate  114 R of the series of plates of the splitter device, and is consequently spaced apart from the plates carried by the first portion of the splitter device. 
     In this extreme spaced-apart position, the splitter device  48  defines a preferred electrical path between the upstream portion and the downstream portion of the electric circuit, which path comprises in alternation conductive sections comprising the distinct conductive elements, in this example all of the distinct conductive elements, all carried by the same relatively movable portion of the plate device, and insulating sections comprising the successive distinct individual free paths defined between the successive plates  114  in pairs. The preferred electrical path also includes an insulating section between the rear end plate  114 R and the front free end  129  of the contactor  128 . 
     In the extreme spaced-apart position, corresponding in this configuration to a maximum value of the spacing between the front free end  129  of the contactor  128  and the rear end plate  114 R, this spacing is determined as a function of the dielectric strength that it is desired to obtain for the apparatus  10  in the open position of the electric circuit. 
     In the example shown, the contactor  128  has a conductive main portion that extends along a layout curve identical to the layout curve of the plates and that presents a section that is constant in planes perpendicular to the layout curve. The main portion presents a length along the layout curve that is not less than the distance along the layout curve between the front end terminal  114 V and the rear end plate  114 R of the series of plates of the splitter device. 
     It can thus be understood that in this third embodiment the preferred electrical path follows the layout curve of the plates  114  over the insulating body of the first portion of the device. Consequently, it can be understood that the contactor  128  presents a shape that is elongate along the path of the preferred electric circuit defined by the layout curve of the plates. 
     In this example, it can be understood that the preferred electrical path coincides with the path of at least one of the two portions of the splitter device performing its relative spacing movement, e.g. specifically to the path of a point of the contactor  128  relative to the insulating body  110 ,  112 . As a result, at least some of the distinct individual free paths extend along a path that presents a non-zero component in projection onto a direction perpendicular to the opening movement path of the movable connection member, and they can thus present a total length that is greater than the length that they occupy along the direction of the axis A 1 . It is thus possible to have a total “arc length” that is greater, and/or to increase the number of electric arcs between two successive conductive elements. 
     More particularly, and as described above, when a channel is formed in the insulating body, and the insulating body is made of an insulating material that possesses ablation properties enabling pressure to rise locally and presenting greater dielectric strength than the surrounding fluid present in the enclosure of the apparatus, the channel tends to be even better at directing and cooling any electric arc that might propagate from plate to plate, each electric arc extending between two successive plates and each plate then forming a relay between two successive arcs. Such a channel makes it possible in particular to avoid an electric arc appearing between two distinct conductive elements  114  that are not in succession along the layout curve. It thus makes it possible potentially to reduce the pitch of the helix when the layout curve is helical. This effect is even stronger when the outside diameter of the outside surface  118  of the inner portion  110  is close to the inside diameter of the inside cylindrical surface  122  of the outer portion  112  of the insulating body. The effect is maximized if these two diameters are equal, in which case the channel presents a section that is closed by virtue of the contact between the outside surface  118  of the inner portion  110  and the inside surface  122  of the outer portion  112 . 
     It should be observed at this point that the path followed by the contactor  128  is a helical path, at least so long as the contactor  128  is not fully disengaged from the series of distinct conductive elements  114 . In contrast, the path of the movable connection member is, overall, a movement in translation along the axis A 1 . 
     It may be observed that the fact that the contactor  128  is engaged in the holes in the plates  114  represents an embodiment associated with the arrangement of the plates across the passage of the contactor  128  along the insulating body. Nevertheless, it is also possible to envisage that the plates are arranged not across the passage followed by the contactor  128  along the insulating body, but in the immediate proximity of that passage, without any electrical contact between the plate(s) and the contactor  128 , e.g. at a distance of less than 10 mm, possibly less than 5 mm, and even less than 2 mm. This proximity is selected so that when the end  129  of the contactor  128  passes close to a given plate, any electric arc between that end and a preceding plate along the curve becomes attached to said given plate. This ensures that the successive arcs are attached from plate to plate along the layout curve between the front end plate and the front end  129  of the contactor  128  until the arcs become completely extinguished when the accumulated length is long enough. 
       FIG. 21  shows a possible arrangement for such a splitter device in a breaker apparatus of the type described with reference to  FIGS. 1 and 2 . This figure shows that the first portion  50  of the splitter device  48  may be housed inside the internal cavity  31  in the first electrode  20 . The second portion  52  of the splitter device  48  may then be housed at least in part inside an internal cavity  41  in the connection member  24 . The connection member  24  may present, at least in its front portion, a tubular bushing  43  of axis A 1  that may be made of conductive material, within which the cavity  41  is provided so as to be forwardly open towards the first electrode  20 . In the embodiment shown, provision (not shown) may be made for the contactor  128 , and optionally its drum  130 , to be axially movable relative to the tubular bushing  43  of the movable connection member  24 , e.g. by making provision for the contactor  128  to move relative to the bushing  43 , or indeed by making provision for the bushing  43  to be telescopic. Such a provision makes it possible to ensure that in an extreme open position of the movable connection member, when fully retracted rearwards, the movable contactor  128  is received as much as possible inside the cavity  41 . In contrast, when the movable connection member is caused to move towards its closed position, the bushing  43  may be brought into contact axially forwards with a bearing surface of the first electrode  20  or of the first portion  50  of the splitter device, starting from an intermediate position of the movable connection member  24 , with it also being possible for the movable contactor  128  to continue its movement towards the relative contact position shown in  FIG. 18 . 
     In a variant it is possible to make provision for the first portion of the splitter device  48 , comprising the insulating body  110 ,  112  carrying the plates  114 , to be mounted so as to movable in rotation about the axis A 1  in the breaker apparatus, with the contactor  128  of the second portion then potentially being stationary in rotation about the axis A 1 . 
     In a variant, the first portion  50  of the device  48  comprising the insulating body carrying the plates  114  could be selected to be movable axially in the apparatus, e.g. by being carried by the movable connection member  24 , with the contactor  128  then being stationary, it being possible for it then to be mounted in stationary manner in the apparatus, e.g. in the internal cavity  31  in the first electrode  20 . 
     This third embodiment does not have an end-of-stroke absorber device for the stroke of the movable connection member. Nevertheless, such a device could be provided by using the same concept as described with reference to the first and second embodiment. 
     Each of the above-described splitter devices defines a desired electrical path when it is not in its contacting position, and electric current can flow along the desired electrical path in the event of dielectric breakdown resulting from a large difference in electric potential exceeding the dielectric strength between the two portions of the device. Along this desired electrical path, electric current flows either by being conducted in distinct conductive elements that are solid, or else in the form of electric arcs in the individual free path(s). The desired electrical path may be considered as a path of least dielectric strength between the upstream portion and the downstream portion of the electric circuit for the spaced-apart position(s) of the portions of the splitter device. 
     In the above examples, it is also possible to implement the disclosure in a breaker apparatus in which there is no direct contact between the movable connection member and the stationary electrode in the electrically closed position of the electrodes of the mechanical apparatus, with electrical contact then being established only via the splitter device. Under such circumstances, the nominal electric current flows through the apparatus along the continuous electrically-conductive path defined by the two portions of the splitter device in the contacting position, which would then constitute a main continuous electrically-conductive path along which said distinct conductive elements are arranged. 
     In the embodiments, it can be seen that the main or secondary continuous electrically-conductive path is formed by the object(s) made of solid and conductive materials through which the nominal electric current flows when the two members of the apparatus are in the electrically closed position and/or the two portions of the splitter device are in the electrical contact position. Insofar as the continuous electrically-conductive path has a plurality of solid and conductive physical objects, these objects are electrically in contact with one another. The continuous electrically-conductive path thus has a physical aspect, that of the solid and conductive physical object making it up, and a geometrical aspect, that of the shapes of those objects. 
     In the embodiments, the distinct conductive elements extend over only a portion of the continuous electrically-conductive path in the apparatus. The remainder of the continuous electrically-conductive path includes in particular the electrodes, the connection terminals, and the movable connection member. 
     In the meaning of the disclosure, the distinct conductive elements are arranged along the main or secondary continuous electrically-conductive paths, in the sense that for at least certain states of the apparatus in which the two portions of the splitter device are in an electrically contacting relative position, the distinct conductive elements: 
     form portions of solid and conductive physical objects in which the continuous electrically-conductive current flows, as in the first and second embodiments; and/or 
     as in the third embodiment, they are arranged in the immediate proximity of, for example, in mechanical contact with, or even in electrical contact with one or more solid and conductive physical objects through which the nominal electric current flows. For example, in the operating conditions when opening the apparatus, it is considered that proximity is immediate when the end of the contactor  128  going past the plate  114  causes the electric arc to become attached thereto. 
     In the embodiments, the continuous electrically-conductive path, at least for the portion along which the distinct conductive elements are arranged, is a path that is single, in the sense that it does not have any parallel branches, at least in this portion. 
     In the embodiments, the distinct individual free paths correspond to geometrical paths along which there are no solid and conductive physical objects, but only insulating fluid. 
     It can thus be considered that in the electrical contact relative position between the two portions of the splitter device, the distinct individual free paths are of zero length. 
     In the embodiments, each of the distinct individual free paths is created during the opening movement of the two members of the apparatus, in the sense that the length of the individual free paths varies during the opening movement by going from a zero value to a value where a total arc voltage built up throughout the splitter device  48  can reach a value such as to cause the electric arc to disappear. In an active state of the splitter device  48 , the total dielectric strength of the individual free paths in the absence of any arc may become significant, for example greater than 1 kV/mm. 
     Each of the distinct individual free paths may be created progressively during the opening movement of the two members of the apparatus. This progressive creation of distinct individual free paths starting from a zero value, as made possible by the arrangement of the distinct conductive elements along the continuous electrically-conductive path in which the nominal current flows immediately prior to the loss of contact between the two portions of the splitter device, makes it possible to control where arcs are created and does not require action by a system for moving an arc towards a remote chamber as in the prior art. 
     In the embodiments in which the splitter device has a first portion  50  and a second portion  52  that are movable relative to each other, each of the distinct individual free paths is created more particularly by the movement spacing the two portions of the device apart. 
     The distinct individual free paths, or at least some of them, may be created successively one after another over time, in particular with a time offset associated with the opening movement of the two electrodes of the apparatus, or with the movement spacing the two portions of the splitter device apart when the device has a first portion and a second portion that are movable relative to each other. This applies in the third embodiment where the distinct individual free paths are created in succession one after another as the contactor moves rearwards during the movement spacing the contactor away from the first portion  50  of the splitter device. 
     The distinct individual free paths, or at least some of them, may be created simultaneously, as in the circumstances illustrated by the above-described first and second embodiments. 
     In the embodiments, for a spaced-apart position, the sum of the lengths of the distinct individual free paths of the desired electrical path is greater than the length of the movement for spacing apart the two relatively movable portions of the splitter device between their contact position and their spaced-apart position. This increase in the “arc length”, and the possibility of also increasing the number of arcs by increasing the number of individual free paths between two proximal distinct conductive elements makes it possible to increase the capacity of the splitter device, and thus of the breaker apparatus, to extinguish an electric arc created during opening by opposing a large arcing voltage immediately or almost immediately, as in the first and second embodiments, or progressively, as in the third embodiment. These two advantages may be obtained for given compactness of the apparatus, in particular compactness along the travel direction of the movable connection member. 
     In the embodiments described, it can be understood that the splitter device, at least in an opening position prior to an extreme opening position, creates a multitude of distinct individual paths between a multitude of distinct conductive elements that are electrically insulated from one another. The apparatus of the disclosure may have at least five distinct individual paths, possibly at least ten distinct individual paths, or even at least thirty distinct individual paths. 
     The disclosure is not limited to the examples described and shown since various modifications may be applied thereto without going beyond its ambit. 
     From the above description, it can be seen clearly that regardless of the embodiment of the splitter device, there may be advantage in arranging the splitter device inside an internal cavity arranged in the first electrode or in the second electrode. 
     Therefore, it may be advantageous to have a mechanical breaker apparatus for a high voltage or very high voltage electric circuit, the apparatus being of the type comprising two electrodes  20 ,  22 ,  24  that are to be connected electrically respectively to an upstream portion and to a downstream portion of the electric circuit, the two electrodes of the mechanical apparatus being movable relative to each other in an opening movement between at least one electrically open position and at least one electrically closed position in which they make a nominal electrical connection of the apparatus  10 , said nominal electric connection serving to pass a nominal electric current through the apparatus, and of the type including an electric arc splitter device  48  having a multitude of distinct conductive elements that, for at least one active state of the splitter device, are spaced apart and electrically insulated from one another so as to define, in a surrounding insulating fluid, a multitude of successive distinct individual free paths in which electric arcs can be struck on opening and/or closing the electric circuit, and of the type comprising a sealed enclosure containing an insulating fluid and in which there are arranged at least the first electrode  20  and the second electrode  22 , said apparatus being characterized in that at least some of the distinct conductive elements of the splitter device  48  are housed in an internal cavity arranged in the first electrode or the second electrode. 
     In such an apparatus, the splitter device may be designed as described in the above examples, which may have the advantage of being very compact, thereby facilitating housing them in an internal cavity of relatively small dimensions, but other designs are also possible. 
     In such an apparatus, the internal cavity may be arranged inside an envelope defined by a conductive peripheral surface of the first electrode. In a variant, at least the second electrode includes a movable connection member  24  that is movable in an opening movement relative to the first electrode between an extreme electrically open position and an extreme electrically closed position in which it establishes a nominal electrical connection with the first electrode  20 , and the internal cavity is arranged inside an envelope defined by a conductive insulating peripheral surface of the movable connection member  24 .