FR2689305A1 - Three=phase cut=off for medium voltage circuit breaker - has three separate identical poles each with evacuated enclosure contacting separable contacts within air-cooled chamber - Google Patents

Abstract

The cut-off has three poles which are enclosed in a metal box, with each pole comprising a moulded insulating chamber (10) housing the enclosure (14) which has insulating side-walls (14), preferably in ceramic, and being enclosed at each end by plates or caps (16,17). A fixed metal rod (18) and contact (19) is attached to one plate (16). A moving metal rod (22) and contact (21) with a bellows seal (23) slides through the other plate (17). A copper tube (35A), threaded at one end to take a connector (32), is soldered to the first plate (16). A metal bar (31) makes a soldered connection to the second (17). The moving contact is operated by a self-adjusting rod (30) with a restoring spring (26) and casing (25). Air flows through the copper tube and through grooves in the chamber. USE/ADVANTAGE - Particularly for unpluggable circuit breakers. Smaller size, lower cost, and flexible use without specialised tools.

Description

THREE-PHASE SWITCHING MODULE AND APPLICATION IN PARTICULAR TO A CIRCUIT BREAKER
MEDIUM PLUG-IN VOLTAGE
The present invention relates to a three-phase breaking module and to its application to the production of medium-voltage circuit breakers, in particular withdrawable circuit breakers.

 The number of prefabricated withdrawable circuit breaker stations installed in the world is large and may justify the development of vacuum cut-off devices replacing the existing devices generally equipped with circuit breakers with low oil volume. The vacuum cutoff technique is now very developed and will replace the oil cutoff technique which requires more bulky and not very ecological devices.

 An object of the present invention is to design a vacuum circuit breaker which could replace the current circuit breakers with low oil volume equipping the withdrawable medium voltage cells. Thus, the user will be able to replace his existing circuit breakers, without necessarily replacing all the other elements of the cell.

 Another object of the invention is to provide a low-cost vacuum circuit breaker, compact, easy to produce anywhere from widely industrialized standard components, very flexible use compatible without significant tools with many configurations.

 The subject of the invention is a three-phase vacuum cut-off module, characterized in that it comprises three identical poles arranged in a metal box, each pale comprising a molded insulating enclosure comprising a first tubular part in which is housed a vacuum interrupter comprising, inside a sealed envelope closed by a first and a second flange, a first contact, fixed, and a second contact, mobile, and connected by a metal rod sealingly passing through said second flange and connected to a maneuvering insulating rod, said enclosure comprising a second tubular part connected to the first by a leave and in which is disposed a metal tube of which a first end is mechanically connected to the vacuum interrupter and electrically connected to said fixed contact of the interrupter vacuum, a second end of said tube carrying a first connection element, the vacuum interrupter comprising a second connection element consisting of a metal bar secured to said second flange and electrically connected to said rod, the operating rods of the three phases being connected to a common operating mechanism located in a sub-compartment of the housing, the parts of the poles containing said tubes projecting outside the housing through holes in one of its side walls.

 Advantageously, said first part of the insulating enclosure has internal grooves and parallel to the enclosure, defining with the exterior wall of the vacuum interrupter ventilation channels, the air entering the tube through holes at one end. , passing through the tube, leaving the tube through holes at its other end and entering said grooves.

 When the bulb is small, it is placed in a resin cage arranged in the first part of the enclosure.

 Said resin cage has internal grooves parallel to its axis, defining with the wall of the vacuum interrupter ventilation channels, the air entering said tube through holes at one end and re-entering the grooves through holes at its other end.

 Preferably, the insulating rod is provided with a play take-up device.

 The enclosure comprises, in the vicinity of the fillet, a metal grid, inserted in the molding, and set to the potential of said metal tube.

 The electrical connection between the second connection element and the metal rod of the movable contact of the vacuum interrupter is ensured by means of a sleeve fixed to said second flange, a ring secured to said sleeve and a contact of the type accordion or ring disposed inside said ring and surrounding said rod, the second connection element (31) being secured to said sleeve (50A).

 Toroidal current measurement windings are arranged around the poles, outside the housing.

 The invention also relates to a withdrawable circuit breaker, characterized in that it comprises a chassis provided with rolling means and containing a module of the aforementioned type, the second connection elements of the module being connected by bars to crossings integral with the chassis, external to it and parallel to the ends of the poles of the module, current sensors being arranged on said bushings.

 In a particular embodiment, said bars supply a relay without an auxiliary source directly actuating the operating mechanism contained in the sub-compartment.

 As a variant, said rods connecting the poles to the bushings are in series with a striker fuse capable of actuating the operating mechanism contained in the sub-compartment.

 According to another variant, the connecting bars of the poles to the bushings are provided with radiator elements, such as fins.

The invention also relates to a withdrawable circuit breaker characterized in that it comprises a chassis provided with rolling means, inside which are placed two modules of the aforementioned type, the ends of the poles protruding from said chassis and being arranged parallel to each other. , the module housings being modified so that the operating rods are connected to only one and the same control mechanism
The invention also relates to a cassette for a withdrawable circuit breaker, characterized in that it comprises a metal frame provided with means for horizontal or vertical movement, inside which is a withdrawable circuit breaker of the type described above, the ends of the poles and bushings being respectively connected to external conductors fixed to the frame for connection to a busbar and to a cable outlet.

 In this embodiment, each pole end or crossing comprises two current transformers.

 The invention also relates to a circuit breaker for outdoors, characterized in that it comprises a metal casing provided with feet and an interior insulating cladding inside which is disposed a module of the type described above, the poles of the module protruding from said envelope to constitute a terminal of the circuit breaker, the circuit breaker comprising other crossings connected inside the envelope to the poles of the module by bars and constituting a second terminal of the circuit breaker.

 Advantageously, the ends of the poles of the module are provided with a sleeve reinforcing their insulation.

 The invention also relates to a withdrawable circuit breaker, characterized in that it comprises a chassis provided with rolling means, inside of which there are two modules of the aforementioned type electrically connected in parallel.

The invention is now specified by the description of an embodiment of the circuit breaker of the invention as well as of various cells using such a circuit breaker, with reference to the appended drawing in which:
FIG. 1 is a view in axial section of a pole of a circuit breaker according to the invention,
- Figure 2 is a partial sectional view of a pole of a circuit breaker according to an alternative embodiment
FIG. 3 is a view in axial section of a device ensuring the passage of the current from the movable contact of the vacuum interrupter towards an outlet of the pole,
FIG. 4 is a perspective view of an element for constituting a three-phase circuit breaker according to the invention, this element being designated in the following by "three-phase breaking module",
FIG. 5 is an elevation view of a withdrawable circuit breaker comprising a three-phase breaking module,
FIG. 6 is an elevation view of a withdrawable circuit breaker comprising a three-phase breaking module and equipped with a relay without an auxiliary voltage source,
FIG. 7 is an elevation view of a breakable fuse or contactor comprising a three-phase cut-off module,
FIG. 8 is an elevation view of a large-size withdrawable circuit breaker comprising a three-phase breaking module,
FIG. 9 is an elevation view of a withdrawable circuit breaker with high breaking capacity from small vacuum interrupters comprising two three-phase breaking modules,
FIG. 10 is an elevation view of a cassette associated with a withdrawable circuit breaker,
FIG. 11 is an elevation view of a circuit breaker for the exterior comprising a three-phase breaking module,
- Figure 12 is an elevational view of a withdrawable circuit breaker of high caliber comprising two three-phase breaking modules.

 FIG. 1 represents a pole of a polyphase circuit breaker which comprises as many poles as there are phases.

The poles of the same polyphase circuit breaker are identical in the following, we will show several examples of three phase circuit breakers for equipping medium voltage cells.

 In FIG. 1, the reference 10 designates an envelope of insulating material, such as resin or an elastomer, produced by molding.

 A first part 10A of the envelope has a tubular shape and defines a cylindrical cavity containing a vacuum interrupter 14 shown diagrammatically.

 The vacuum interrupter comprises an insulating enclosure 15, preferably made of ceramic, closed by two end plates or flanges 16 and 17; to the plate 16 is fixed, inside the enclosure, a metal rod 18 carrying a fixed metal contact 19.

 The vacuum interrupter 14 has a movable metallic contact 21 carried at the end of a movable metallic rod 22 sliding through the plate 17, in leaktight manner thanks to a bellows 23.

The metal rod is fixed, preferably by means of a play take-up device, for example of the type comprising a cage 25 provided with a spring 26, to an operating rod 30 made of insulating material
The inner surface of the part 10A of the enclosure 10 is provided with grooves 12 parallel to the axis of the envelope and serving as ventilation channels, as will be explained below.

 A first pole outlet is constituted by a metal bar 31 welded to the plate 17, and taking the current on the rod 22 by a mechanism 50 described in more detail with reference to FIG. 3.

 The enclosure 10 comprises a second part lOB, tubular, but with an outside diameter smaller than the outside diameter of the part lOA, and connected to the latter by a leave 10C. This tubular part defines a cylindrical cavity inside which is a metal tube 35, preferably made of copper, welded to the end plate 16 of the vacuum interrupter.

 For assembly, the tube is first welded to the vacuum interrupter provided with its socket 31, then the assembly is inserted into the insulating envelope 10; the operation is facilitated by the use of an insulating grease, for example based on silicone, which will further promote the dielectric strength of the device.

 To the tube 31 is fixed, preferably by screwing, a connector 32 consisting for example of a copper tube split at its end; the tube 32 is provided with peripheral holes 32A whose role will be explained below.

 It will be noted that the dimensions of the part 10A of the enclosure 10, and in particular its internal diameter and its internal depth, are preferably chosen to allow the vacuum ampoules having the largest dimensions to be accommodated. If we want to accommodate a vacuum bulb of smaller dimensions, we will interpose, as shown in Figure 2, between the interior of the bushing 10A and the vacuum bulb 14, a cylindrical cage 13, of insulating material such as the resin, provided with external grooves 13A defining with the lateral surface of the vacuum interrupter ventilation channels.

 Reference will be made to FIG. 3 which shows how the metal tube 22 is electrically connected to the socket outlet 31.

 Vacuum bulbs usually include a metal cover welded to the plate 17 and which contains a bearing for the movable rod 22. For the purposes of the invention, the cover is modified and transformed into a sleeve 50A internally threaded to which one can screw a metal ring 50B. A contact 50C, of the accordion type for example, is placed between the tube 22 and the ring 50B. The socket 31 is welded to the ring 50A.

 Returning to FIG. 1, it can be seen that the tube 35 carries, in the vicinity of the plate 16, holes 35A whose role is explained now.

 When the nominal current passes through the vacuum bulb, it undergoes heating due to the Joule effect. The cooling of the bulb is ensured by an air circulation which engages in the tube 35 through the holes 32A, crosses the holes 35A and engages in the grooves 12 (or in the grooves 13A when one is in the case of the alternative embodiment of Figure 2). This ventilation circuit is of primary importance because it eliminates the risks of pollution and condensation.

 The examination of FIG. 1 shows the presence, between the flange 16 and the intermediate portion 10C of the envelope, of a volume filled with air. Without special precautions, this volume would be subject to a strong potential gradient which could lead to partial discharges which, in the long run, can be destructive. To avoid this drawback, the envelope comprises, in line with the aforementioned volume, a metal grid 40 inserted in the molding, and which is brought to the potential of the metal tube 35. In this way, the potential differences are applied to the insulating parts only. .

 FIG. 4 shows a three-phase breaking module for the constitution of a withdrawable three-phase circuit breaker; the module comprises three identical poles 61, 71 and 81, conforming to the pale described with reference to FIGS. 1 to 3.

 The poles are placed side by side in a metal box 90 forming a drawer, and comprising a bottom 91, two short sides 92 and 93 and two long sides 94 and 95. The box is set to earth potential. It is used horizontally.

 The thinned portions 61A, 71A, 81A of the poles, also called hereinafter crossed, pass through the short side 92 of the box through suitable openings. Coils with toroidal magnetic circuits 62, 72 and 82 are slid around the thinned portions of the pole enclosures, outside the box; they constitute current sensors used to trip the circuit breaker, as will be indicated below.

 The poles are fixed inside the box by well known means not shown, for example by belting.

 The first sockets 63, 73 and 83 constitute a flat sheet; the second sockets 64, 74, 84 are arranged parallel to each other.

 A compartment 100 is arranged in the drawer, at its end close to the short side 93, to receive the end of the control rods 65, 75 and 85 of the poles, as well as the operating mechanism; the control and relaying members are placed in a sub-compartment of compartment 100.

These elements are well known and are outside the scope of the present invention; we could refer for example to
Engineering techniques, High voltage electrical switchgear, by Eugène MAURY, D 657-4, page 49.

 FIG. 5 illustrates the production of a complete withdrawable circuit breaker according to the invention.

 The withdrawable circuit breaker comprises a three-phase breaking module 90 mounted in a movable chassis 110, for example provided with rollers 111. In FIG. 5, there is one of the poles 81, the toroidal winding 82, the connector 83, the socket current 84, the control rod 85 and the control compartment 100. The other poles are not visible since they are placed behind the light 81. In the following, we will only describe in detail the elements relating to a phase of the circuit breaker; it should be noted that each element relating to one phase is found, unless the opposite is expressly indicated, on the other phases.

 To the frame 110 is fixed a three-phase set 112 of insulating bushings provided with an end contact 113, arranged parallel to the parts 61A, 71A and 81A of the poles, at a suitable isolation distance Y. The insulating bushing is extended inside the chassis by a set of three-phase bars 114 connected to the current taps of the three-phase breaking assembly 90. The bushings 112 are provided with toroidal windings 115 for measuring the current and the information is sent to the relay sub-compartment. As a variant, the bars 114 inside the chassis can be equipped with a three-phase wound current transformer symbolically represented by the rectangle 116 in dashed lines.

 FIG. 6 shows a withdrawable circuit breaker according to the invention, equipped with direct relays, that is to say without an auxiliary current source, directly controlling the pole operating mechanism contained in compartment 100. The circuit breaker of FIG. 6 has the same elements as that of Figure 5, with, in addition to relays such as 120 placed above the poles. These relays are, for example, overcurrent protection relays.

 FIG. 7 illustrates the mobile part of a ruptofuse or contactor; as before, it comprises a movable chassis containing a three-phase cut-off module 90; the module's vacuum interrupters can be contactor type bulbs and, in this case, the command contained in compartment 100 can be an electromagnetic command; the bushings 112 are extended, inside the chassis 110, by striker fuses 125 electrically connected to the sockets 84 by bars 126; the striker fuses are fitted with strikers 127 directly attacking the operating mechanism contained in compartment 110.

Isolation is provided by a crossing 128.

 FIG. 8 illustrates a withdrawable circuit breaker according to the invention, for large currents, for example greater than or equal to 3150 amps. It includes the same elements as the circuit breakers of Figure 5, but the bars 114 connecting the bushings 112 to the sockets 84 are surrounded by elements of radiators 130, such as fins.

 FIG. 9 represents a withdrawable circuit breaker with high breaking capacity using small vacuum bulbs; it comprises, in a movable frame 110, two three-phase cut-off modules 90 'and 90 ", in which the drawer has been shortened so as to shelter only the poles; the ends 112' and 112" of the modules protrude outside the chassis and are arranged parallel to each other, at a distance Y sufficient to ensure the dielectric strength; the control rods 85 'and 85 "are connected to an operating arm 131 driving the same control compartment (100'). The other elements of the circuit breaker are the same as those of the circuit breaker shown in FIG. 5.

 FIG. 10 represents a cassette associated with the circuit breaker; this cassette, consisting of a parallelepiped metal frame 132, contains a chassis 110 equipped as described with reference to Figure 5; the cassette comprises means for precisely guiding the rollers 111; the bushings 81A and 112 are connected respectively to sockets 135 and 136 fixed to a wall 133 of the cassette 132, and extended by bars 137 and 138 intended to be connected respectively to a busbar and to a cable outlet; the bushings 112 and 81A are each provided with two current transformers, respectively 139, 140 and 141, 142; transformers 82 and 115 no longer serve as backup.

 The device operates horizontally or vertically; in the latter case, it is provided with a set of additional guide rollers 111 'and a forklift symbolized by the jack 145; a shutter 146 isolates the wall 133 from the frame 110.

The cassette which has just been described meets the standards
CEI, ANSI and others.

 Figure 11 is a view of a circuit breaker for outdoors (in English station breaker) at 15, 24 or 36kV.

 I1 comprises a metal structure 150 supported by feet 151 and internally lined with standard insulating cladding 152; this structure is closed by an upper plate 153. Inside the structure 150, there is a cut-off module 90, the crossings 81A of which pass through the upper plate; sealing and electrical insulation are provided by a base 154. The insulation of the bushing 81A is reinforced by an insulating sleeve 155 provided with fins, for example made of elastomer.

 The socket 84 of the module is connected by a bar 156 to a bushing 157 insulated by a sleeve 158 provided with fins, also made of elastomer. Sealing and insulation are ensured by a base 159. The module is provided with two current transformers 161 and 162 constituted by wound cores surrounding the pole; the bar 156 is also provided with two current transformers 163 and 164 constituted by wound cores.

 It will be noted that the sleeves 155 and 158 can, as a variant, be made of porcelain.

 FIG. 12 illustrates a circuit breaker of high rating, that is to say one whose nominal current is equal to or greater than 4000 amps.

 The circuit breaker comprises two three-phase breaking modules 90A and 90B each provided with a vacuum bulb at 3000 amps and connected to a common control 100; the current is equally distributed between these two modules which are electrically connected in parallel.

 The starting bar 114 is provided with elements of radiators 130; there are 4 input current transformers 171, 172, 173 and 174, and 2 output current transformers 175 and 176. The current transformers 82A and 82B of the modules serve as balancing current transformers.

 A partition 180 separates the module area from the bushing area.

The invention is technically very efficient because the basic modules integrate most of the usual functions that an equipment master must master in electrical installations, namely
- cut-off function, which is performed here by the vacuum interrupter,
- support function or sectioning element by drawing out,
- command function,
- current sensor function
This basic module can be easily integrated into all common use cases:
- withdrawable circuit breakers
- external circuit breakers
- separate circuit breakers
On the industrial level, the apparatuses which are the subject of the invention are very homogeneous due to the widespread use of the same simple components or of the same family achievable in several basic technologies. In particular, the pole enclosures can be made of epoxy or polyurethane; the crossings of the modules' poles can be reinforced by molded plastic sleeves or by porcelain.

 It is therefore easy to install such devices in the world, either in new installations or in replacement of existing installations.

 The apparatuses according to the invention are finally particularly suited to international standards and in particular North American.

Claims (18)

1 / Three-phase vacuum cut-off module, characterized in that it comprises three identical poles (61, 71, 81) arranged in a metal box (90), each pole comprising a molded insulating enclosure (10) comprising a first tubular part (10A) in which is housed a vacuum interrupter (14) comprising, inside a sealed envelope (12) closed by a first (16) and a second (17) flange, a first contact (19), fixed, and a second contact (21), mobile, and connected by a metal rod (22) sealingly passing through said second flange (17) and connected to an insulating operating rod (65, 75, 85), said enclosure comprising a second tubular part (lOB) connected to the first by a leave (10C) and in which is disposed a metal tube (35) of which a first end is mechanically connected to the vacuum interrupter and electrically connected to said fixed contact (19) of the vacuum interrupter, a second end of said tube (35) carrying a first connection element (63, 73, 83), the vacuum interrupter comprising a second connection element (64, 74, 84) consisting of a metal bar secured to said second flange (17) and electrically connected to said rod (22), the operating rods (65, 75, 85) of the three phases being connected to a common operating mechanism located in a sub-compartment (100) of the housing, the parts (61A, 71A, 81A) blades containing said tubes (35) projecting outside the housing through holes in one (92) of its side walls. 2 / Module according to claim 1, characterized in that said first part (10A) of the insulating enclosure (10) has grooves (12) inside and parallel to the enclosure, defining with the outer wall of the bulb to empty the ventilation channels, the air entering the tube (35) through holes (32A) at one end, passing through the tube, leaving the tube through holes 35A at its other end and entering said grooves (12). 3 / Module according to claim 2, characterized in that the vacuum interrupter is placed in a resin cage (13) disposed in the first part (10A) of the enclosure (10). 4 / Module according to claim 3, characterized in that said resin cage (13) has internal grooves (13A) parallel to its axis, defining with the wall of the vacuum interrupter ventilation channels, the penetrating air in said tube (35) through holes (32A) at one end and entering the grooves (13A) through holes (35A) at its other end. 5 / Module according to one of claims 1 to 4, characterized in that the insulating rod (30) is provided with a play take-up device (25). 6 / Module according to one of claims 1 to 5, characterized in that the enclosure (10) comprises, in the vicinity of the fillet (1OC), a metal grid (51A), inserted during molding, and the potentialization of said tube metallic (35). 7 / Module according to one of claims 1 to 6, characterized in that the electrical connection between the second connection element (31) and the metal rod (22) of the movable contact of the vacuum interrupter, is ensured by means a sleeve (50A) fixed to said second flange (17), a ring (50B secured to said sleeve (50A) and a contact of the accordion or ring type (50C) disposed inside said ring and surrounding said rod (22), the second connection element (31) being secured to said sleeve (50A). 8 / Module according to one of claims 1 to 7, characterized in that toroidal windings (62, 72, 82) for measuring the current are arranged around the poles, outside the housing (90). 9 / withdrawable circuit breaker, characterized in that it comprises a chassis 110 provided with rolling means (111) and containing a module according to one of claims 1 to 8, the second connection elements (84) of the module being connected by bars (114) at crossings (112) integral with the chassis (110), external to the latter and parallel to the ends (81A) of the poles of the module, current sensors (115) being arranged on said crossings (112) . 10 / withdrawable circuit breaker according to claim 9, characterized in that said bars supply a relay without auxiliary source (120) directly actuating the operating mechanism contained in the sub-compartment (110). 11 / A circuit breaker according to claim 9, characterized in that said bars (126) connecting the poles to the bushings are in series with a striker fuse (125) capable of actuating the operating mechanism contained in the sub-compartment (100). 12 / A circuit breaker according to claim 9, characterized in that the bars (114) connecting the poles to the bushings (112) are provided with radiator elements (130), such as fins. 13 / withdrawable circuit breaker characterized in that it comprises a chassis (110) provided with rolling means (111), inside which are placed two modules (90 ', 90 ") according to one of claims 1 to 8 , the ends (112 ', 112 ") of the poles protruding from said chassis and being arranged parallel to each other, the module housings being modified so that the operating rods (85', 85") are connected to only one and same control mechanism (100 '). 14 / Cassette for withdrawable circuit breaker, characterized in that it comprises a metal frame (132) provided with means of horizontal (111) or vertical movement (111, 111 ', 145), inside which is arranged a circuit breaker withdrawable according to claim 9, the ends of the poles (81A) and of the bushings (112) being respectively connected to external conductors 137, 138) fixed to the frame for connection to a busbar and to a cable outlet. 15 / Cassette according to claim 14, characterized in that each pole end (81A) or crossing (112) comprises two current transformers. 16 / Circuit breaker for outdoor use, characterized in that it comprises a metal casing (150) provided with feet (151) and an interior insulating cladding (152), inside of which is arranged a module according to one of claims 1 to 8, the poles of the module protruding from said enclosure to constitute a terminal of the circuit breaker, the circuit breaker comprising other crossings (157) connected inside the enclosure to the poles of the module by bars (156 ) and constituting a second terminal of the circuit breaker. 17 / A circuit breaker according to claim 16, characterized in that the ends (81A) of the poles of the module are provided with a sleeve (155) reinforcing their isolation. 18 / Withdrawable circuit breaker, characterized in that it comprises a chassis (110) provided with rolling means (111), inside which there are two modules (90A, 90B) according to one of claims I to 8 , electrically connected in parallel.