Medium-voltage switch contact assembly

Abstract

A medium voltage switch contact assembly (1) comprising a contact arm (2), a contact element (3) and a sensing device arrangement (4) wherein the contact arm (2) comprises an electrically conductive elongate body (21) extending along a longitudinal axis (50) and having a first end (211) connected to an electrical terminal and a second end (212) opposite the first end (211), and an insulating protector (22); an insulating protector (22) surrounding at least a portion of the elongated body (21); a contact element (3) positioned at a second end (212) of the electrically conductive elongate body (21) and adapted to be coupled / uncoupled with a corresponding mating contact by a rectilinear movement along the longitudinal axis (50), the sensing device arrangement (4) comprising a sensor device (41) provided with a fixing strap (42), the securing band (42) forms a loop surrounding the electrically conductive elongate body (21) and removably secures the sensing device arrangement (4) to the electrically conductive elongate body (21).

Description

Technical Field

[0001] The present invention relates to a medium-voltage switch contact assembly provided with an innovative sensor system. More specifically, the present invention relates to a medium-voltage switch contact assembly provided with an improved and properly positioned sensing device arrangement. In yet another aspect, the present invention relates to a medium-voltage switchgear, in particular a medium-voltage circuit breaker, provided with a switch contact assembly as described herein. Background Art

[0002] For the purposes of the present invention, the term "medium voltage" is intended to denote an electrical system operating at voltage levels higher than 1 kV AC and 1.5 kV DC up to several tens of kV (e.g., up to 72 kV AC and 100 kV DC).

[0003] It is well known that medium-voltage switching devices (e.g., circuit breakers, disconnectors, contactors) are typically provided with sensing equipment to detect operating conditions (e.g., current, voltage) and / or environmental conditions (e.g., temperature, pressure).

[0004] In a typical application in the medium-voltage field, for example in a draw-out circuit breaker application, the disconnector contact arrangement is provided with Figure 8 a switch contact assembly of the type shown.

[0005] In such an arrangement, the switch contact assembly 100 typically includes a contact arm 120 constituted by a conductive elongated body 160 enclosed in an insulating protective housing 130. A contact element 170 is located at the operating end of the contact arm 120 and is movable between a disconnected position and an inserted position in a corresponding fixed contact (not shown).

[0006] The switch contact assembly 100 includes a temperature sensor 140 that is embedded in the conductive elongated body 160 of the contact arm 120 and is insulated by the assembled insulating protective housing 130.

[0007] One of the main drawbacks of this known solution is that it requires a specifically designed insulating protective housing 130 as well as a specifically designed conductive elongated body 160.

[0008] Furthermore, alternative insulating protection for the assembled insulating housing 130 (e.g., overmolded insulating protection) cannot be used.

[0009] Another drawback is that the contact arm 120 needs to be disassembled to install the temperature sensor 140 after commissioning.

[0010] In practice, when a temperature sensor needs to be installed after commissioning, such a solution requires replacing the contact arm 120 in order to install the temperature sensor 140 using jigs during the assembly process.

[0011] It is also worth noting that, compared with sensorless solutions, these solutions require many dedicated additional components (such as silicon rings, O-rings, etc.), thus increasing the cost and complexity.

[0012] To improve the design of a switch contact assembly equipped with a sensor device, various attempts have been made and many suggestions have been put forward. However, the proposed solutions are not always completely satisfactory in terms of performance, design complexity, installation cost and time, maintenance cost and time, and similar drawbacks. Summary of the Invention

[0013] The main object of the present invention is to provide a medium-voltage switch contact assembly that can overcome or at least mitigate the drawbacks of the prior art.

[0014] In this context, an object of the present invention is to provide a medium-voltage switch contact assembly provided with a sensor device, in particular a temperature sensing device that is suitably positioned.

[0015] Another object of the present invention is to provide a medium-voltage switch contact assembly provided with a sensor device that does not require a specially designed insulation protection member.

[0016] Another object of the present invention is to provide a medium-voltage switch contact assembly provided with a sensor device that does not require a specially designed one or more conductive components.

[0017] Another object of the present invention is to provide a medium-voltage switch contact assembly provided with a sensor device in which an assembled or overmolded insulation protection member can be used.

[0018] Another object of the present invention is to provide a medium-voltage switch contact assembly provided with a sensor device in which the sensor device can also be easily assembled / disassembled after commissioning.

[0019] Another object of the present invention is to provide a medium-voltage switch contact assembly provided with a sensor device in which the number of additional components (such as silicon rings, O-rings, and similar parts) required is minimized compared to sensorless solutions.

[0020] Another object of the present invention is to provide a medium-voltage switch contact assembly provided with a sensor device that has a relatively simple structure, is easy to manufacture at the industrial level and has a low cost, and is easy to maintain and has a low cost.

[0021] According to the present invention, the above objects and purposes, as well as other purposes that will become apparent from the following description and drawings, are achieved by a medium-voltage switch contact assembly according to claim 1 and related dependent claims below.

[0022] In still other aspects, the present invention also relates to a medium voltage switchgear including a medium voltage switch contact assembly as described herein.

[0023] In a general definition of the present invention, a medium voltage switch contact assembly according to the present invention includes a contact arm, which in turn includes: a conductive elongated body extending along a longitudinal axis, the conductive elongated body having a first end connected to an electrical terminal and a second end opposite to the first end; and an insulating protective member surrounding at least a portion of the elongated body.

[0024] Furthermore, the medium voltage switch contact assembly of the present invention includes: a contact element positioned at the second end of the conductive elongated body and adapted to be coupled / decoupled with a corresponding mating contact by a linear movement along the longitudinal direction; and a sensing device arrangement.

[0025] Specifically, the currently disclosed medium voltage switch contact assembly is characterized in that the sensing device arrangement includes a sensor device provided with a fixing band that forms a loop around the conductive elongated body and detachably fixes the sensing device arrangement to the conductive elongated body.

[0026] For the purposes of the present invention, the terms "first end" and "second end" are not intended to denote the physical limits of the conductive elongated body, but rather the operating points of the conductive elongated body that perform the specified functions.

[0027] Moreover, for the purposes of the present invention, the term "detachably fixed" is intended to mean that the sensing device arrangement is not embedded in a specific component of the entire contact assembly (e.g., in the contact arm).

[0028] Thus, as better described below, in the medium voltage switch contact assembly of the present invention, the design and positioning of the sensing device arrangement - in particular, the use of a winding element to detachably fix it at a specific position on the conductive elongated body - provides an effective system for providing a sensing device for the switch contact assembly that can be easily installed and removed without cumbersome operations.

[0029] In the following detailed description, the present invention will be described with reference to a medium voltage switchgear (e.g., a circuit breaker) provided with a contact assembly equipped with a temperature sensor, but in general, it can be applied to any type of medium voltage switchgear and any type of sensing device required according to the operating needs.

[0030] In practice, the medium voltage switch contact assembly of the present invention has a "modular" structure, i.e., even after CB commissioning, the sensor can be installed on the "basic" version of the switch contact assembly without disassembling the contact arm and thus without using fixtures.

[0031] In practice, a modular solution can be obtained by arranging the sensing device arrangement at an appropriate position on the conductive elongated body between the contact element (e.g., tulip-shaped contact element) and the insulating protective housing.

[0032] In this way, the sensing device arrangement can be installed by simply removing the contact element (e.g., tulip-shaped contact element), without the need for fixtures for on-site installation.

[0033] At the same time, the sensing device arrangement can be removed or replaced without having to remove the contact arm and the insulating protective housing.

[0034] In addition, it is worth noting that no special design of the insulating protective housing and the conductive components (i.e., the conductive elongated body) is required, and overmolded insulating protective parts or assembled insulating protective parts can be used according to operational needs.

[0035] Furthermore, the currently disclosed medium-voltage switch contact assembly is also advantageous from an economic perspective, because in addition to the sensor itself, it does not require additional components (e.g., silicon rings, O-rings, and similar components) compared to standard solutions.

[0036] In some embodiments of the medium-voltage switch contact assembly of the present invention, the insulating protective part may include an insulating housing assembled to at least a part of the conductive elongated body.

[0037] Alternatively, in other embodiments of the medium-voltage switch contact assembly of the present invention, the insulating protective part is overmolded onto at least a part of the conductive elongated body.

[0038] According to some highly preferred embodiments of the medium-voltage switch contact assembly of the present invention, the sensing device arrangement can be advantageously fixed to the conductive elongated body near the second end of the conductive elongated body.

[0039] In other general embodiments of the currently disclosed medium-voltage switch contact assembly, the insulating protective part may conveniently include a cup-shaped protrusion positioned around the second end of the conductive elongated body.

[0040] In this case, the cup-shaped protrusion may have a design including the following: a bottom wall having a hole for the conductive elongated body to pass through; a side wall surrounding the conductive elongated body at a certain distance; and an opening opposite the bottom wall for the contact element to pass through.

[0041] In these later embodiments of the medium-voltage switch contact assembly of the present invention, the sensing device arrangement can be appropriately positioned in the cup-shaped protrusion of the insulating protective part.

[0042] Specifically, the sensing device arrangement structure can be located within the cup-shaped protrusion of the insulating protection member between the bottom wall of the cup-shaped protrusion and the contact element. In practice, in these embodiments, the cup-shaped protrusion of the insulating protection member forms a chamber around the second end of the conductive elongated body, and the sensing device arrangement structure can be conveniently positioned within this chamber.

[0043] In a general embodiment of the currently disclosed medium-voltage switch contact assembly, the contact element (e.g., a tulip-shaped contact element) can be detachably mounted on the second end of the conductive elongated body.

[0044] Thus, when the insulating protection member includes a cup-shaped protrusion positioned around the second end of the conductive elongated body, removing the contact element from the second end of the conductive elongated body can provide access to the cup-shaped protrusion through the opening. Therefore, the sensing device arrangement structure can be installed, removed, or replaced by simply disassembling the contact element (e.g., the tulip contact element) without the need for fixtures for on-site installation and without having to remove the contact arm and / or the insulating protection housing.

[0045] Specifically, in these embodiments of the medium-voltage switch contact assembly of the present invention, the cup-shaped protrusion can conveniently extend over at least a portion of the contact element.

[0046] According to some specific embodiments of the medium-voltage switch contact assembly of the present invention, the fixing strap of the sensing device arrangement structure can be made of a magnetic material. In this way, the magnetic fixing strap forming a loop around the conductive elongated body can serve as the magnetic core of a power supply device that obtains electrical energy from the current flowing along the conductive elongated body. For this purpose, the power supply device further includes a secondary winding conductor that is wound around at least a portion of the magnetic material fixing strap and is used to feed the required electrical energy to the sensing device and / or related electronics.

[0047] In other general embodiments of the currently disclosed medium-voltage switch contact assembly, the sensor device of the sensing device arrangement structure can conveniently include a housing in which the sensing device and related electronics can be housed. The housing can then be operatively connected to the fixing strap such that it can be detachably fixed to the conductive elongated body, as better described in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] More features and advantages of the present invention will become more apparent from the description of the preferred but non-exclusive embodiments of the present invention shown by way of example in the drawings, in which:

[0049] - Figure 1 is a cross-sectional view of an embodiment of a medium-voltage switch contact assembly according to the present invention;

[0050] -Figure 2 is an exploded view of an embodiment of a medium - voltage switch contact assembly according to the present invention;

[0051] - Figure 3 is an enlarged cross - sectional view of details of an embodiment of a medium - voltage switch contact assembly according to the present invention;

[0052] - Figure 4 is a perspective view of an embodiment of a medium - voltage switchgear including a medium - voltage switch contact assembly according to the present invention;

[0053] - Figure 5 is a side view of an embodiment of a medium - voltage switchgear including a medium - voltage switch contact assembly according to the present invention;

[0054] - Figure 6 is a partially - sectioned side view of an embodiment of a medium - voltage switchgear including a medium - voltage switch contact assembly according to the present invention;

[0055] - Figure 7 is a partially - exploded perspective view of an embodiment of a medium - voltage switchgear including a medium - voltage switch contact assembly according to the present invention;

[0056] - Figure 8 is a cross - sectional view of a medium - voltage switch contact assembly according to the prior art. Detailed Description of the Invention

[0057] Referring to the accompanying drawings, the present invention in its more general definition relates to a medium - voltage switch contact assembly 1.

[0058] In Figures 4 - 7 the illustrated embodiment, the medium - voltage switch contact assembly 1 is part of a medium - voltage switchgear 10 having a draw - out circuit breaker unit 50 mounted on a movable trolley 11. Each phase of the circuit breaker unit 50 is provided with a pair of medium - voltage switch contact assemblies 1 which are adapted to be coupled / decoupled with corresponding mating contacts (not shown) in the switchgear according to design and functional principles well - known in the art (and thus will not be described in more detail).

[0059] Specifically referring to Figures 1 - 3 , the medium - voltage switch contact assembly 1 of the present invention includes a contact arm 2.

[0060] Furthermore, the contact arm 2 includes a conductive elongated body 21 which extends along a longitudinal axis 50 which, in Figures 4 - 7 the illustrated embodiment, is substantially aligned with the direction of movement of the trolley 11 on which the circuit breaker unit 50 is mounted.

[0061] The conductive elongated body 21 has a first end 211 electrically connected to an electrical terminal (not shown), such as the electrical terminal of the circuit breaker unit 50, and a second end 212 opposite to the first end 211.

[0062] In addition, the conductive elongated body 21 is provided with an insulating protection member 22 that surrounds at least a part of the conductive elongated body 21.

[0063] Depending on the application, in some cases, the insulating protection member 22 may include an insulating housing assembled to at least a part of the conductive elongated body 21.

[0064] Alternatively, in some other applications of the medium - voltage switch contact assembly 1 of the present invention, the insulating protection member 22 may be overmolded onto at least a part of the conductive elongated body 21.

[0065] In fact, one of the advantages of the present invention is that the currently designed solution can be used with an overmolded insulating protection system or an assembled insulating protection system.

[0066] The medium - voltage switch contact assembly 1 of the present invention further includes a contact element 3 located at the second end 212 of the conductive elongated body 21. The contact element 3 is adapted to be coupled / decoupled with a corresponding mating contact in the switchgear unit 10 by a linear movement along the longitudinal axis 50.

[0067] In the embodiment of the switch contact assembly 1 shown in the drawings, the contact element 3 is a so - called tulip - type contact. Tulip - type contacts are well - known in the art and thus will not be described in more detail.

[0068] In addition, the medium - voltage switch contact assembly 1 of the present invention further includes a sensing device arrangement 4, which may be, for example, a temperature sensor arrangement. Depending on the operating requirements, other types of sensors, such as pressure sensors, voltage sensors, or current sensors, may be used.

[0069] A unique feature of the medium - voltage switch contact assembly 1 of the present invention is that the sensing device arrangement 4 includes a sensor device 41 provided with a fixing strap 42.

[0070] In the shown embodiment, the fixing strap 42 forms a loop surrounding the conductive elongated body 21 in place and is provided with a closing device 421; thus, the sensing device arrangement 4 can be detachably fixed to the conductive elongated body 21.

[0071] In practice, the sensor device 41 can be fixed to the conductive elongated body 21 by the metal wristband 42 and held in place. The metal wristband 42 is wound around the conductive elongated body 21 and closed by a reversible closing device 421. In this way, the sensor device 41 can be very easily and quickly fixed to or removed from the conductive elongated body 21.

[0072] Different from the prior art solutions, in the medium voltage switch contact assembly 1 of the present invention, the sensing device arrangement structure 4 is not embedded in the contact arm 2, but is fixed at an easily accessible position of the conductive elongated body 21, without having to disassemble the entire contact arm 2 after commissioning to install the sensing system.

[0073] Specifically, as shown in the attached Figures 1 - 3 figures, the sensing device arrangement structure 4 is conveniently positioned near the second end 212 of the conductive elongated body 21 and is thus easily accessible.

[0074] Always referring to the embodiments of the drawings, in the medium voltage switch contact assembly 1, the insulating protection member 22 includes a cup-shaped protrusion 220 that is positioned around the second end 212 of the conductive elongated body 21.

[0075] Specifically, the cup-shaped protrusion 220 includes a bottom wall 221 provided with a hole for the conductive elongated body 21 to pass through. Side walls 222 extend from the bottom wall 221 and surround the second end 212 of the conductive elongated body 21 at a certain distance. On the opposite side relative to the bottom wall 221, the side walls 222 form an opening 223 for the contact element 3 (especially the tulip-shaped contact element 3) to pass through.

[0076] In practice, the cup-shaped protrusion 220 of the insulating protection member 22 forms a kind of chamber around the second end 212 of the conductive elongated body 21, in which the sensing device arrangement structure 4 can be conveniently positioned.

[0077] In a particularly preferred embodiment of the medium voltage switch contact assembly 1 of the present invention, the sensor device 41 and the fixing band 42 constituting the sensing device arrangement structure 4 are positioned on the conductive elongated body 21 within the cup-shaped protrusion 220, at a position between the bottom wall 221 of the cup-shaped protrusion 220 and the second end 212 of the conductive elongated body 21 (i.e., the position where the contact element 3 is installed).

[0078] In addition, the contact element 3 is removably mounted on the second end 212 of the conductive elongated body 21 by a reversible fixing device 5 (such as a screw device or a similar device).

[0079] Thus, removing the contact element 3 from the second end 212 of the conductive elongated body 21 provides free access to the interior of the cup-shaped protrusion 220 through the opening 223 defined by the side wall 222 of the cup-shaped protrusion 220, thereby allowing the installation, removal, or replacement of the sensing device arrangement 4 located inside the cup-shaped protrusion 220.

[0080] Accordingly, contrary to known solutions, the operation of installing, disassembling, or replacing the sensing device arrangement 4 can be carried out very easily and can also be carried out after commissioning, without the need for jigs and without having to remove the entire contact arm 2 and / or the insulating protective housing 22. In practice, in the embodiment shown in the figures, it is only necessary to detach the tulip contact element 3 from the terminal portion 212 of the conductive element 21, and the required operations of installing / removing / replacing the sensing device arrangement 4 can be carried out by opening / closing the fixing strap 42 via the closing device 421.

[0081] Advantageously, as shown, the cup-shaped protrusion 220 extends over a part of the contact element 3, thereby allowing the contact element 3 to be coupled / decoupled from the corresponding mating contact while protecting the sensing device arrangement 4 housed in its internal space.

[0082] In a preferred embodiment of the medium-voltage switch contact assembly shown in the figures, the sensor device 41 includes a housing that houses the sensing device (e.g., a temperature sensor) and associated electronics. The housing is operatively connected to the fixing strap 42 so that it can be fixed to / removed from the conductive elongated body 21 as described previously.

[0083] For example, in a particular embodiment of the medium-voltage switch contact assembly, when the fixing strap 42 of the sensing device arrangement 4 is made of a magnetic material (as briefly described previously), the fixing strap 42 can be partially positioned inside the housing, and the secondary winding conductor can be wound around the portion of the fixing strap located inside the housing. The secondary winding conductor is then used to supply the required electrical energy to the sensor and / or associated electronics.

[0084] Therefore, it can be clearly seen from the above that the medium-voltage switch contact assembly of the present disclosure fully achieves the intended goals and purposes.

[0085] In fact, the sensor is contained in a part of the contact arm, which is not visible when assembled (and thus protected from the external environment), but at the same time is easily accessible for installation, disassembly, or replacement operations.

[0086] Furthermore, since the currently disclosed solution can be applied to both overmolded insulating protective parts and assembled insulating protective parts, there is no need to change the technology of the insulating protective parts.

[0087] From a manufacturing perspective, the currently disclosed medium voltage switch contact assembly is very easy to manufacture and requires only a very limited number of components, thus having an advantage in terms of cost.

[0088] The system of the present invention is particularly effective in medium voltage switchgear, and thus a medium voltage switchgear including a medium voltage switch contact assembly as disclosed herein is a specific object of the present invention.

[0089] As needed, any shape, material, and size are possible, and any variations in this regard should be considered part of the present invention.

Claims

1. A medium voltage switch contact assembly (1), comprising: - A contact arm (2), which includes: - A conductive elongated body (21) that extends along a longitudinal axis (50) and has a first end (211) connected to an electrical terminal and a second end (212) opposite to the first end (211); - An insulating protection member (22) that surrounds at least a portion of the conductive elongated body (21); - A contact element (3) that is positioned at the second end (212) of the conductive elongated body (21) and is adapted to be coupled / decoupled with a corresponding mating contact by a linear movement along the longitudinal axis (50), - A sensing device arrangement (4), characterized in that the sensing device arrangement (4) includes a sensor device (41), the sensor device (41) being provided with a fixing strap (42), the fixing strap (42) forming a loop around the conductive elongated body (21) and removably fixing the sensing device arrangement (4) to the conductive elongated body (21).

2. The medium voltage switch contact assembly (1) according to claim 1, wherein, The sensing device arrangement (4) is fixed to the conductive elongated body (21) near the second end (212) of the conductive elongated body (21).

3. The medium voltage switch contact assembly (1) according to claim 1 or 2, wherein, The insulating protection member (22) includes an insulating housing assembled to at least a portion of the conductive elongated body (21).

4. The medium voltage switch contact assembly (1) according to claim 1 or 2, wherein, The insulating protection member (22) is overmolded onto at least a portion of the conductive elongated body (21).

5. The medium-voltage switch contact assembly (1) according to one or more of the preceding claims, wherein, The insulating protection member (22) includes a cup-shaped protrusion (220) surrounding the second end (212) of the conductive elongated body (21).

6. The medium voltage switch contact assembly (1) according to claim 5, wherein, The cup-shaped protrusion (220) includes: a bottom wall (221) having a hole for the conductive elongated body (21) to pass through; a side wall (222) surrounding the conductive elongated body (21) at a distance; and an opening (223) opposite to the bottom wall (221) for the contact element (3) to pass through.

7. The medium voltage switch contact assembly (1) according to claim 5 or 6, wherein, The sensing device arrangement (4) is positioned in the cup-shaped protrusion (220).

8. The medium voltage switch contact assembly (1) according to claim 7, wherein, The sensing device arrangement (4) is positioned in the cup-shaped protrusion (220), between the bottom wall (221) of the cup-shaped protrusion (220) and the contact element (3).

9. The medium voltage switch contact assembly (1) according to one or more of the preceding claims, wherein, The contact element (3) is removably mounted on the second end (212) of the conductive elongated body (21).

10. The medium voltage switch contact assembly (1) according to one or more of claims 5 to 8 and claim 9, wherein, Removing the contact element (3) from the second end (212) of the conductive elongated body (21) provides access to the cup-shaped protrusion (220) through the opening (223).

11. The medium voltage switch contact assembly (1) according to one or more of claims 5-10, wherein, The cup-shaped protrusion (220) extends over at least a portion of the contact element (3).

12. The medium-voltage switch contact assembly (1) according to one or more of the preceding claims, wherein, The fixing strap (42) of the sensing device arrangement (4) is made of a magnetic material.

13. The medium voltage switch contact assembly (1) according to one or more of the preceding claims, wherein, The contact element (3) is tulip-shaped.

14. The medium-voltage switch contact assembly (1) according to one or more of the preceding claims, wherein, The sensor device (41) includes a housing that houses the sensing device and related electronics, and the housing is connected to the fixing strap (42).

15. A medium-voltage switchgear (10) comprising a medium-voltage switch contact assembly (1) according to one or more of the preceding claims.

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