Patent Application
20190355534
The disclosure relates to the technological field of breaker apparatuses for high voltage electric circuits.
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 (SF6), 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.
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.
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 A1, and the two electrodes 20, 22 together with their associated terminals 28, 30 present elongate shapes, respectively along an axis A2 and along an axis A3. In this example, the axes A2 and A3 are parallel. The axes A2 and A3 are perpendicular to the central axis A1 of the wall 14 and they are offset from each other along the direction of the axis A1. In addition to being offset in this way along the direction of the central axis A1, the terminals 28 and 30 are arranged opposite from each other on either side of the central axis A1.
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 A1 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 A1 that is guided to slide along the central axis A1, which is arbitrarily referred to herein as being “longitudinal”, in a cylindrical internal cavity of axis A1 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
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 A1 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 A1 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
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
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
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 A1 between at least one electrical contact position, shown in
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
In contrast, for positions of the movable connection member 24 lying between the extreme closed position shown in
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
By way of example, the bars 54 are carried by a U-shaped frame 55 that extends in a plane containing the central axis A1 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
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 A1, 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 A1, 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 A1 so as to enable the bars to be mounted on two parallel rods of axis A1 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 A1 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 A1 and to the transverse direction. As can be seen in
As can be seen in particular in
It can be seen in
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
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 A1, from a first contact position between the two portions as shown in
In the position of
On moving towards the rear, towards the position shown in
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 A1 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 A1 inside the socket 58 between an offset advanced position shown in
The various operational positions of the splitter system 48 are described below with reference to
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
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
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 A1. The electrical contact position as shown in particular in
Starting from this relative position of the various components of the apparatus, as shown in
It should thus be observed that the movement of the connection member 24 towards its extreme closed position shown in
In this embodiment, it should thus be observed that between the positions of
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
Starting from the state described with reference to
On reaching the position of
When the movable connection member 24 continues its rearward opening movement, in the opening direction, beyond the position of
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□lCLE
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
lCLE 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□lCLE 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
Under all circumstances, when the movable connection member 24 continues its retraction movement from the position of
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
The primary plates 94 may be all identical in shape. As can be seen in
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 A1, 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 A1 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
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 A1 and possesses an angular extent around the axis A1 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 A1 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 A1.
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 A1. 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 A1, 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 S2 about the axis A1 and they are axially offset by an axial offset D along the direction of the axis A1. 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
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
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
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
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.
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
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
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 A1 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 A1 and bounded by the axis A1, being offset relative to one another axially along the axial direction A1 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 A1 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.
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 A1 that is mounted on the movable connection member 24 so as to be capable of turning about the axis A1. The turning of the drum 130 about the axis A1 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.
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
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.
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 A1 and movement in rotation about the axis A1, 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
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 114V 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.
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 114R 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 114R, 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 114V and the rear end plate 114R 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 A1. 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 A1.
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.
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 A1 in the breaker apparatus, with the contactor 128 of the second portion then potentially being stationary in rotation about the axis A1.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1557622 | Aug 2015 | FR | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15750848 | Feb 2018 | US |
| Child | 16507252 | US |
