WO2010079271A1

WO2010079271A1 - Electric meter with means for electrically connecting/disconnecting to/from current and voltage circuits

Info

Publication number: WO2010079271A1
Application number: PCT/FR2009/052184
Authority: WO
Inventors: Jean-Louis Guillon
Original assignee: Itron France
Priority date: 2009-01-06
Filing date: 2009-11-16
Publication date: 2010-07-15
Also published as: FR2940837B1; FR2940837A1

Abstract

The invention relates to an electric meter that comprises a current circuit and a voltage circuit combined with a phase, and connection/disconnection means (6") capable of assuming a first position in which the current circuit and the voltage circuits are connected, or a second position in which the current circuit and the voltage circuit are electrically disconnected. According to the invention, the connection/disconnection means include a mobile metal plate (6") translatably movable on a same plane between the first position and the second position, the metal plate (6") including a cutout defining two connection tabs (61, 62) parallel to each other and orthogonal to the longitudinal direction of the conductor, and connectable to said input or output conductor by elastic snap-coupling or detent.

Description

ELECTRIC COUNTER WITH MEANS OF

ELECTRICAL CONNECTION / DISCONNECTION OF CIRCUITS

CURRENT AND VOLTAGE

The present invention relates to the field of electric meters, and more particularly the means equipping such counters for irreversibly or irreversibly switching a calibration mode of the meter in an operational mode.

An electric meter comprises, in a conventional manner, at least one current circuit and one voltage circuit. In the case of a single-phase electric meter, the latter comprises a single pair or assembly consisting of a current circuit and a voltage circuit, whereas in the case of a polyphase meter, the counter has as many of pairs or subsets of current circuit / voltage circuit as there are phases. The electrical power consumed on each phase is calculated from a measurement of current flowing through the current circuit, and a measurement of voltage across the voltage circuit.

When the electric meter is in its normal operating mode, that is to say connected to the general power grid, the current and voltage circuits of the same pair or subassembly must be electrically connected.

On the other hand, during the test before installation or following a repair of an electric meter, it is necessary to calibrate the voltage and current circuits of the same pair, and this, independently. Accordingly, in calibration mode, the voltage and current circuits of the same pair or subassembly must be electrically isolated.

The function which makes it possible to electrically connect or disconnect the current and voltage circuits of the same pair is known under the terminology of the "common point" function, or else in the English terminology "I / P link", which means an electrical link may or may not exist between the current circuit I and the voltage or phase circuit P.

In the remainder of the discussion, we are particularly interested in the specific means by which this "common point" function can be performed. Since these means must function as a switch enabling the connection and disconnection operations, they will be designated accordingly in the following by the more general terminology of electrical connection / disconnection means.

A first known solution for making an electrical connection / disconnection, used in counters marketed by the Applicant, is shown in Figures la to Ic. More specifically, FIGS. 1a and 1b illustrate the connection / disconnection means associated with a phase of a counter, respectively in the connected and disconnected position, and FIG. 1c partially illustrates the integration of these means at the terminal box. counter. In FIGS. 1a-1c, references 1a, 1b denote the input and output conductors of the current circuit (not shown), between which a current measurement sensor (not shown) is placed in series. These two conductors 1a, 1b, preferably made of copper or brass, can constitute directly the input and output conductors of the current measurement sensor. These two conductors 1a, 1b are each electrically connected to two metal terminals 2a, 2b which respectively constitute the input and output terminals of a phase of the network. These input and output terminals are accessible from the terminal box 3 of the meter via two access ports E, S for connecting the meter to a phase of the electrical distribution network (see Figure Ic). A metal strip 5, for example of brass, is maintained extending longitudinally between the two input and output terminals 2a, 2b and parallel to these terminals. One of the ends of this bar 5 is accessible from the terminal box 3 via an access port Bv. This bar 5 thus constitutes a voltage terminal. A metal screw 5a attached to the other end of this bar 5 is intended to receive a first end of an electrical connection 5b, the other end being connected to the voltage circuit (not shown). The electrical connection / disconnection means here consist of a metal part 6 capable of forming or not forming an electrical bridge between the current terminal 2a, and the strip 5 forming a voltage terminal according to the position it occupies. The metal part 6 extends transversely with respect to the terminals, and has an oblong opening 6a through which extends a first metal screw 7 for fixing the part to the voltage terminal 5. In the connected position shown in FIG. 1a, the electrical bridge between the current circuit and the voltage circuit is provided via the workpiece 6 by means of the metal screw 7 for fixing, and a second metal screw 8 for fixing the workpiece 6 to the input terminal 2a. In order to obtain the disconnected position of FIG. 1b, it is necessary to unscrew the screws 7 and 8, then move the workpiece 6 by translation until it is no longer in electrical contact with the terminal 2a. In this position, the current circuit is disconnected from the voltage circuit, and it is possible to calibrate these two circuits independently. In this embodiment, the calibration of the voltage circuit is carried out in particular by applying a calibration voltage to the strip 5 forming a voltage terminal, through the access opening B _v .

It is noted that this realization is first of all expensive considering the number of elements necessary to achieve the function "common point". Moreover, it requires complex manipulation for the calibration operation. This operation is all the more tedious for a polyphase counter for which the manipulation must be performed for each phase.

Another known solution has been made in order to simplify the previous connection, both in terms of the number of parts needed, and in terms of handling. In this solution, shown schematically in Figure 2 attached, and described in detail in EP 1 825 278 B1 in the name of the Applicant, there is a terminal box 3 having, for each of the three phases of the counter, two access ports E and S to access the input and output terminals of the phase in question, and a port Bv to access the voltage terminal. On the left side of Figure 2, a portion of the terminal box cover has been removed to make visible the internal elements to this box at one of the phases. Here, the electrical connection / disconnection means consist of an elastic blade 6 'whose ends are, in the rest position of the blade, in contact with, on the one hand, the input conductor 1c of the current circuit ( not shown), and on the other hand, an electrical connection 4 to the voltage circuit (not shown) the voltage terminal, so that the current and voltage circuits are electrically connected. In the disconnected position shown in Figure 2, the end of the blade 6 'has been removed from the electrical connection 4 through the transverse action of a plunger 90 that the maintenance agent has been able to introduce through an opening in the terminal box provided for this purpose. One and the same specific tool 9 carrying as many divers 90 as there are phases in the meter is advantageously provided to allow the maintenance agent to simultaneously connect or disconnect the voltage and current circuits of each phase.

This second solution, although simpler and less expensive in number of parts and especially in the number of operations required for connection or disconnection operations that the first solution described above, however, is not completely satisfactory. In particular, the use of an elastic blade does not sufficiently guarantee a return to the connected position required to allow the meter to operate in its operational mode. In addition, for the two solutions described above, the terminal box remains complicated to achieve since access openings Bv to access the voltage terminals are required for each of the phases.

These voltage terminals were previously needed not only for calibration, but also for the connection of switch-type or remote control relay power management accessories. However, the aforementioned energy management functions are increasingly incorporated into the meters so that the voltage terminals are made to be used only for calibration.

The present invention aims to overcome the above drawbacks by proposing a very simple and inexpensive solution to achieve a "common point" function, which allows in particular to eliminate the need to use a particular voltage terminal accessible from outside the the terminal box.

This object is achieved according to the invention which relates to an electric meter intended to be connected to at least one phase of a distribution network, and comprising, associated with said phase, a current circuit and a voltage circuit, and connection / disconnection means adapted to occupy either a first position in which the current circuit and the voltage circuit are connected, or a second position in which the current and voltage circuits are electrically disconnected, characterized in that said means connection / disconnection consists of a metal plate extending perpendicular to a direction longitudinal of an input or output conductor of said current circuit, said metal plate being electrically connected to the voltage circuit in the first position and in the second position, and being movable in translation in the same plane between the first position and the second position, said metal plate having a cutout forming two connecting tabs extending parallel to each other and orthogonal to the longitudinal direction of the conductor, the two connecting tabs being adapted to hook onto said input or output conductor snap or snap elastic when the metal plate is in the first position.

In the case of a connection by elastic clipping, said metal plate is positioned opposite said input or output conductor so that, during the translation of said metal plate to the first position, the two connecting lugs are suitable to clamp laterally said conductor by elastic clipping.

The cut must be adapted according to whether the input or output conductor has a portion in the form of a flat profile, or a portion of circular section. In the case of an elastic snap connection, the input or output conductor has at least one flat profile portion, provided with a central slot extending in the longitudinal direction of said conductor, and said metal plate is positioned opposite said slot so that, during the translation of said metal plate to the first position, the two connecting tabs are adapted to come into said slot by snap elastically.

In all cases, it can be provided that the connection can be performed irreversibly (prohibiting any subsequent disconnection) or not. The invention and the advantages it provides will be better understood from the description given below of several possible embodiments of the electrical connection / disconnection means equipping an electric meter according to the invention, with reference to the appended figures. in which :

- Figures 1a and 1b, described above, illustrate the principle of operation of the electrical connection / disconnection means according to a first known embodiment, respectively in the connected position and in the disconnected position; - Figure Ic, described above, partially illustrates a terminal box receiving the connection / disconnection means of Figures la and Ib;

- Figure 2, described above, partially illustrates a terminal box of a three-phase meter equipped with electrical connection / disconnection means according to a second known embodiment, in the disconnected position;

- Figures 3a and 3b schematically illustrate electrical connection / disconnection means for equipping an electric meter according to the invention, respectively in the connected position and in the disconnected position;

- Figures 4a and 4b illustrate a first embodiment of the invention of the electrical connection / disconnection means respectively in the connected position and in the disconnected position; FIGS. 5a and 5b illustrate a second variant embodiment according to the invention of electrical connection / disconnection means, respectively in the connected position and in the disconnected position;

FIGS. 6a and 6b partially illustrate a terminal box of a meter equipped with electrical connection / disconnection means according to the invention, respectively in the disconnected position and in the connected position.

With reference to FIGS. 3a and 3b, reference numeral 1 designates one of the input or output conductors of a current circuit (not shown) equipping a counter and intended to be associated with a given phase of the electrical distribution network. . This input or output conductor is preferably copper or brass, and may advantageously constitute directly the input or output conductor of a current measuring sensor, such as that described in the documents FR 2 800 167 , WO 2008/065291 and FR 2 849 925 in the name of the Applicant.

As in the previously described solutions, the electrical meter comprises, associated with said phase, means 6 "of connection / disconnection able to occupy either a first position in which the current circuit and the voltage circuit (not shown) are connected. a second position in which the current and voltage circuits are electrically disconnected.

According to the invention, these connection / disconnection means consist of a metal plate 6 "extending perpendicularly with respect to a longitudinal direction of a conductor 1 input or output of the current circuit. is movable in translation in the same plane between a first connected position (FIG. 3a) and a second disconnected position (FIG. 3b), and comprises a cutout forming two connecting tabs 61, 62 extending parallel to one another and orthogonally relative to each other; to the longitudinal direction of the conductor 1. Here, the input or output conductor 1 has at least one portion of circular section, and the cutout is such that the two connecting tabs 61, 62 define, between their free ends, a forming clamping zone 60 complementary to said portion. In consequently, when the plate 6 "is brought by translation into the connected position illustrated in FIG. 3a, the free ends of the tabs 61, 62 move slightly apart until the clamping zone 60 comes to fit the outline of the conductor 1 In this position, the two legs 61, 62 of connection thus pinch said conductor laterally.

In addition, whether the meter is in operational mode (connected common point) or in calibration mode (common point disconnected), the metal plate 6 "is electrically connected permanently to the voltage circuit, preferably via an electrical lug 50, itself electrically connected to the voltage circuit via a flexible connection 5b, The electrical lug 50 is preferably connected to a connection tongue (not visible in FIGS. 3a, 3b) which is also present the plate 6 ". This connection tongue is advantageously obtained by a particular cut of the plate, and extends in the example along an orthogonal axis on the one hand, to the longitudinal direction of the driver 1 input or output, and other on the longitudinal direction of the two legs 61, 62 of connection. Other orientations of this tongue are however possible by folding the tongue, depending on the space available in the counter for the implantation of the metal plate.

Figures 4a and 4b illustrate an alternative embodiment of the clipping link. In this variant, the input or output conductor 1 has at least one portion in the form of a flat profile, provided with two lateral notches 10, 11 placed symmetrically with respect to the longitudinal direction of the conductor, so as to guide the two legs connection during the translation of the metal plate 6. Preferably, the cut made in the plate 6 "is such that it has two internal notches 63, 64 placed opposite symmetrically to the level of the two legs 61, 62 of connection, the two notches being adapted to engage respectively in the two lateral notches 10, 11. The internal notches 63, 64 are advantageously chamfered to allow unclipping of the plate 6 ". 5a and 5b illustrate another variant according to the invention in which the attachment of the metal plate forming the connection / disconnection means does not take place, as in the two previous variants, by elastic clipping, but by elastic snapping. the input or output conductor 1 of the current circuit has at least one portion in the form of a flat section, provided with a central slot 12 which extends in the longitudinal direction of the conductor 1. The metal plate 6 "is positioned opposite this slot 12 so that, when the metal plate 6 "is brought by translation into the connected position shown in Figure 5a, the two legs 61, 62 of conne xion are plugged into said slot 12 by snap elastically. Due to the elasticity, the tabs then bear against the opposite edges of the slot 12, ensuring the electrical connection. Preferably, the cut made in the plate 6 "is such that it has two notches 65, 66 placed symmetrically at the two tabs 61, 62 of connection, the two notches being able to abut against two opposite edges of the Slot 12 in the connected position As well as the internal notches 63, 64 of the preceding variant, the two notches 65, 66 advantageously have a profile allowing a return of the metal plate 6 "to the second position by elastically unclipping the tabs 61, 62 connection during the translation of the plate. This can be achieved by chamfering the notches.

In a similar manner to the two previous variants, the metal plate 6 "has a connecting tab 67 for receiving the electrical terminal 50 capable of being electrically connected to the circuit. voltage, preferably via a flexible connection 5b. In the illustrated example, given that the plate 6 is this time snapped into the slot, the connection tongue is here obtained by a particular cut and then folded substantially at right angles so as to extend along an axis orthogonal on the one hand, the longitudinal direction of the conductor 1 input or output, and secondly, the longitudinal direction of the two legs 61, 62 connection. However, other orientations of this tongue are however possible by folding more or less the tab, depending on the space available in the counter for the implantation of the metal plate.

In all the preceding variants, the electrical connection / disconnection means for performing the "common point" function is therefore limited to a single piece 6 ", which considerably reduces the manufacturing costs associated with this function. large series, by cutting a plurality of plates simultaneously on the same metal sheet.The sheet is preferably 4/4 hard brass, or phosphor bronze, or any electrically conductive material having the required elastic characteristics.

In addition, the manipulations necessary for the calibration or recalibration of the circuits, then for the transition to the operational mode, are considerably simplified compared to the solutions of the prior art, since it is sufficient to move the plate by a simple translational movement to allow it to occupy the connected position or the disconnected position.

Finally, it is no longer necessary to provide, for calibration, a particular voltage terminal accessible from the terminal box of the meter. Indeed, the plate 6 "alone constitutes a terminal on which one can easily inject a calibration voltage, as will now be explained with reference to Figures 6a and 6b:

These two figures schematically and partially illustrate a terminal box 3 of a meter equipped with means 6 "of electrical connection / disconnection according to the invention, respectively in the disconnected position and in the connected position. E and S allowing access to the input and output terminals of the current measurement circuit associated with a phase of the meter The metal plate 6 "is held and guided in translation inside the terminal box 3, for example by means of guide grooves 30, 31 formed by two parallel inner walls 32, 33 of insulating material of the terminal box 3.

For the circuit calibration mode, the plate 6 "is in the position shown in Figure 6a In this position, it is seen that the plate 6" has a surface area 69 accessible through a rectangular window 34 practiced in the wall 32. This surface area 69 constitutes the contact zone on which a calibration voltage can be injected. Calibration can be carried out simultaneously or sequentially on several phases of the same meter or on several meters by using a calibration bench equipped with a spring-loaded piston system making it possible to establish contact on the contact zone 69.

Once the calibration is completed, the common point is closed by translating the plate 6. This operation can also be automated on the calibration bench using a pneumatic cylinder system.

The plate 6 "is then in the connected position shown in Figure 6b.In this position, we see that the contact zone 69 is no longer accessible. As already indicated above, provision may be made for the plate 6 "to be able to return to the position of FIG 6a, in which case it is advantageous to use, during the manufacture of the plate 6", a slot 68 adapted for the introduction of a tool adapted to control the displacement of the plate 6 "towards its second position with a view to its disconnection As can be seen in FIG. 6b, this slot 68 remains accessible through the rectangular window 34 when the plate 6" is in the connected position.

In addition, special arrangements should be made to prevent fraud attempts by disconnecting the voltage and current circuits for one or more phases, even though the meter appears to be in operational condition. Under these conditions, a cover is generally sealed on the terminal box, to prevent access to the connection / disconnection means, but it must also be ensured that the cover has not been placed while the connection means / disconnection remained in the disconnected position. To do this, it will advantageously provide a removable insulating piece to prevent access to the connection / disconnection means, the establishment of this piece is only possible if the various connection / disconnection means are all in the connected position, that is to say in the low position ensuring the contact with the phase conductor. In particular, it can be expected that it is the establishment of this insulating part that causes the translation of the different metal plates 6 ".

Claims

REVEN DICATIONS

1. Electrical meter intended to be connected to at least one phase of a distribution network, and comprising, associated with said phase, a current circuit and a voltage circuit, and means (6 ") of connection / disconnection apt to occupy either a first position in which the current circuit and the voltage circuit are connected, or a second position in which the current and voltage circuits are electrically disconnected, characterized in that said connection / disconnection means consist of a metal plate (6 ") extending perpendicularly to a longitudinal direction of an input or output conductor (1) of said current circuit, said metal plate (6") being electrically connected to the voltage circuit in the first position and in the second position, and being movable in translation in the same plane between the first position and the second position, said plate (6 ") metal part comprising a cutout forming two connecting tabs (61, 62) extending parallel to each other and orthogonal to the longitudinal direction of the conductor, the two connection tabs (61, 62) being able to hook onto said conductor (1 ) input or output by clipping or snap elastic when the plate (6 ") metal is in the first position.

2. Electricity meter according to claim 1, characterized in that said metal plate (6 ") is positioned facing said conductor (1) input or output so that, during the translation of said plate (6") metal to the first position, the two tabs (61, 62) of connection are adapted to come laterally pinch said conductor by elastic clipping.

3. Electricity meter according to claim 2, characterized in that said conductor (1) input or output has at least one portion of circular section, and in that said cutout is such that the two legs (61, 62). connecting means define, between their free ends, a zone (60) clamping shape complementary to said portion.

4. Electrical meter according to claim 2, characterized in that said conductor (1) input or output has at least one portion in the form of flat profile, provided with two lateral notches (10, 11) placed symmetrically with respect to the longitudinal direction of the conductor, so as to guide the two legs (61, 62) of connection during the translation of said plate (6 ") metal.

5. Electricity meter according to claim 4, characterized in that the cutout has two internal notches (63, 64) placed opposite symmetrically at the two connecting tabs (61, 62), the two internal notches (63, 64) being able to engage respectively in the two lateral notches (10, 11).

6. Electricity meter according to claim 1, characterized in that said conductor (1) input or output has at least one portion in the form of flat profile, provided with a slot (12) central extending in the direction longitudinal direction of said conductor (1), and in that said metal plate (6 ") is positioned facing said slot (12) so that, during the translation of said metal plate (6") to the first position, the two lugs (61, 62) for connection are adapted to come into said slot (12) by snap elastically.

7. Electricity meter according to claim 6, characterized in that the cutout has two notches (65, 66) placed symmetrically at the two tabs (61, 62) of connection, the two notches (65, 66) being able to come abutting against two opposite edges of the slot (12) in the first position.

8. Electricity meter according to claim 7, characterized in that the two notches (65, 66) have a profile allowing a return of the plate (6 ") metal to the second position by resilient detent of the tabs (61, 62) of connection when translating the plate.

9. Electric meter according to any one of the preceding claims, characterized in that said plate (6 ") has a metal tongue (67) connection for receiving a terminal (50) electrical capable of being electrically connected to the voltage circuit.

10. Electricity meter according to claim 9, characterized in that said lug (50) is electrically adapted to be electrically connected to the voltage circuit via a flexible connection (5b).

11. Electricity meter according to any one of the preceding claims, characterized in that said metal plate (6 ") is held and guided in translation inside a terminal box (3) of the meter, and comprises a slot (68) accessible to allow the introduction of a tool adapted to control the movement of the plate (6 ") to the second position.