Electrical switchgear with improved electrical connection device

Abstract

An electrical switchgear, in particular a medium voltage electrical switchgear, comprises a housing comprising at least a main circuit compartment and a conductive cable compartment. For each phase of the electrical circuit, the electrical switchgear comprises a connection device located in the cable compartment, the connection device having a central body provided with a first connection surface suitable for connection with a terminal of the main circuit and a second connection surface suitable for connection with at least a terminal of a conductive cable, the central body having, at its opposite ends, a first shaped body and a second shaped body, respectively having a rounded surface projecting outwardly from the central body.

Description

Technical Field

[0001] This invention relates to an electrical switchgear, particularly a low-voltage or medium-voltage electrical switchgear, which is provided with improved equipment for making electrical connections between the main circuit terminals and cable terminals within the switchgear. Background Technology

[0002] For the purposes of this invention, the term "low voltage or medium voltage" is used to refer to operating voltages up to tens of kV AC. Although this disclosure will primarily refer to medium-voltage switchgear including circuit breakers, the technical solutions disclosed herein are also applicable to general electrical switchgear.

[0003] As is known in the prior art, electrical switchgear, particularly low-voltage and medium-voltage switchgear, is typically divided into multiple compartments to house different components of the switchgear. Generally, electrical switchgear may include busbar system compartments, electrical installation (e.g., circuit breaker) compartments, and cable compartments.

[0004] In cable compartments, cables (e.g., medium-voltage conductive cables) are connected to the main circuit terminals inside the switchgear using a connecting busbar system, such as through the terminals of circuit breakers. Due to the limited space inside the compartment, it is often not possible to maintain sufficient distance between phases to ensure the required insulation. Therefore, insulating partitions are typically used between phases and between a phase and the grounding point to achieve the required insulation conditions.

[0005] However, in some cases, due to the relatively narrow standard width of the switchgear and the rated voltage and current involved, it is sometimes difficult to meet the insulation requirements for safe operation, even with the presence of insulating partitions.

[0006] In addition, additional equipment is typically present in the cable compartment to perform additional functions, such as grounding switches, voltage sensing devices, and transformer (VT) equipment for drawing power to feed one or more auxiliary devices in the switchgear. This additional equipment is usually located in different locations within the cable compartment because it is generally not possible to implement these various functions directly on the connecting busbar system. It is worth noting that the presence of this additional equipment further reduces the available space inside the switchgear's cable compartment, thereby further exacerbating internal insulation problems and / or making it impossible to implement these required additional functions.

[0007] In practice, many existing solutions for electrical switchgear are not entirely satisfactory in terms of insulation performance due to space constraints.

[0008] Furthermore, the need to house multiple devices and equipment within the conductive cable compartment further reduces available space and complicates the assembly and maintenance of the switchgear. Summary of the Invention

[0009] The main objective of this invention is to provide an electrical switchgear, particularly a medium-voltage electrical switchgear, which allows for the resolution or mitigation of the aforementioned problems.

[0010] More specifically, the object of the present invention is to provide an electrical switchgear, particularly a medium-voltage electrical switchgear, which provides a reliable connection system inside the cable compartment of the switchgear between the terminals of one or more conductive cables and the terminals of the main circuit.

[0011] As another objective, the present invention aims to provide an electrical switchgear, particularly a medium-voltage electrical switchgear, which ensures the required insulation between phases and between a phase and the grounding point within the cable compartment of the switchgear.

[0012] As another objective, the present invention aims to provide an electrical switchgear, particularly a medium-voltage electrical switchgear, wherein many functions can be integrated into a connection system between the terminals of one or more conductive cables inside the cable compartment of the switchgear and the terminals of the main circuit.

[0013] As another objective, the present invention aims to provide an electrical switchgear, particularly a medium-voltage electrical switchgear, wherein assembly and maintenance time is reduced.

[0014] Another object of the present invention is to provide an electrical switchgear, particularly a medium-voltage electrical switchgear, which, compared to prior art solutions, can be easily manufactured at an industrial level at a competitive cost.

[0015] To achieve these objectives and purposes, the present invention provides an electrical switchgear, particularly a medium-voltage electrical switchgear, comprising an enclosure including at least a main circuit compartment and a conductive cable compartment. The electrical switchgear of this disclosure is characterized in that, for each phase of the circuit, it includes a connection device located within the cable compartment. The connection device has a central body having a first connection surface adapted for connection to terminals of the main circuit and a second connection surface adapted for connection to at least terminals of the conductive cable. The central body has a first shaped body and a second shaped body at its opposite ends, each having a rounded surface projecting outward from the central body.

[0016] In this way, an improved electrical switchgear, particularly a medium-voltage electrical switchgear, can be provided, which overcomes the problems and shortcomings of the existing connection system between the cable terminals and the main circuit terminals inside the switchgear.

[0017] In practice, in electrical switchgear according to this disclosure, the shape of the connecting equipment, particularly the rounded shape of the first and second shaped bodies protruding from the central body of the connecting equipment, affects the electric field and allows for better control of the phase-to-ground performance within the cable compartment of the switchgear.

[0018] In addition, as better described below, the shape of the connection device allows for the integration of multiple additional functions within the connection device itself, which were previously distributed among different devices located in different locations within the cable compartment of the switchgear.

[0019] In a preferred embodiment of the electrical switchgear disclosed herein, the central body of the connecting device and the first and second molded bodies are preferably made of a single piece of conductive material, depending on the requirements (i.e., rated voltage and current), such as aluminum or silver-plated aluminum.

[0020] In various embodiments of the electrical switchgear disclosed herein, the rounded surfaces of the first and second shaped bodies of the connecting device are part of an elliptical or spherical surface. Other rounded surfaces are also acceptable, as long as they can generate a more uniform electric field around the connecting device.

[0021] In particular, according to an embodiment of the electrical switchgear of the invention, the central body of the connecting device preferably extends along the longitudinal direction x in an xyz reference frame. The central body of the connecting device is advantageously defined upward by the xz plane, and laterally by first and second parallel planes yz at opposite ends of its longitudinal extension.

[0022] Furthermore, in such embodiments, both the first and second molded bodies preferably include a first portion protruding above the xz plane, the first portion having a first convex surface. Additionally, both the first and second molded bodies preferably include a second portion located below the xz plane. The second portions of both the first and second molded bodies protrude outward from the first and second parallel planes yz, respectively, relative to the central body. Moreover, the second portions of both the first and second molded bodies have a second convex surface that is radiated to the corresponding first convex surface of the first and second molded bodies.

[0023] In other words, according to such an embodiment, the first and second forming bodies of the connecting device are advantageously located at relative positions to the central body and project upward and outward relative to the central body, and both the first and second forming bodies are provided with a continuous rounded surface, such as a portion of an elliptical surface, which improves the uniformity of the electric field around the connecting device.

[0024] In this configuration, the central body of the connecting device is conveniently shaped such that the first connecting surface is advantageously located in the xz plane, and the second connecting surface is located in the xy plane perpendicular to the plane of the first connecting surface.

[0025] According to the present invention, in an embodiment of the electrical switchgear, a single connection point between the connecting device and the cable terminal is conveniently provided on the second connecting surface of the central body. Alternatively, multiple connection points between the connecting device and the cable terminal can be provided on the second connecting surface of the central body.

[0026] Therefore, in summary, the second connection surface of the central body of the connection device may include one or more connection points for connection with one or more conductive cables.

[0027] According to this disclosure, in a preferred embodiment of the electrical switchgear, at least a portion of the rounded surface protruding outward from the central body can be cut out in the first shaped body and / or the second shaped body.

[0028] In practice, as better described below, in such embodiments, the first and / or second shaped bodies have cutouts in their rounded surfaces, which can serve as supports for accommodating various pieces of equipment, and the rounded surfaces provide effective equal electric field shielding around the entire accommodating pieces of equipment.

[0029] In particular, in a preferred embodiment of the electrical switchgear disclosed herein, at least a portion of the second convex surface of the first shaped body and / or the second portion of the second shaped body may be cut out.

[0030] For example, when the grounding switch is located inside the cable compartment of the electrical switchgear of the present invention, the first molded body may be provided with a fixed contact adapted to couple with the corresponding movable contact of the grounding switch. Advantageously, the fixed contact can be conveniently accommodated in a cut-out portion of the first molded body, particularly in a cut-out portion of a second portion of the first molded body.

[0031] As another exemplary embodiment of the connection device used in the electrical switchgear of the present invention, the second molded body may be provided with a coupling surface suitable for coupling with a voltage detection device. Advantageously, the coupling surface can be conveniently accommodated in a cut-out portion of the second molded body, particularly in a cut-out portion of a second portion of the second molded body.

[0032] As another exemplary embodiment of the connection device used in the electrical switchgear of the present invention, the second molded body may be provided with a connection hole adapted to receive a transformer for drawing power to feed power to auxiliary equipment of the electrical switchgear. Advantageously, the connection hole can be conveniently accommodated in a cut-out portion of the second molded body, particularly in a cut-out portion of a second portion of the second molded body.

[0033] In this way, in addition to the basic function of connecting cable terminals to the main circuit terminals inside the electrical switch cabinet, many additional functions can be performed by the connection equipment (e.g., supporting the fixed contacts of the grounding switch, providing a signal of voltage presence, supporting the connection of the transformer, etc.), while providing a balanced electric field that allows overcoming the aforementioned phase-to-phase insulation problems and phase-to-ground insulation problems. Attached Figure Description

[0034] Further features and advantages of the invention will become apparent from the description of preferred, but not exclusive, embodiments of electrical switchgear, particularly medium-voltage switchgear, according to the invention, in which non-limiting examples of the invention are provided in the accompanying drawings, wherein:

[0035] Figure 1 This is a schematic side view of an embodiment of an electrical switchgear according to the present invention;

[0036] Figure 2 This is a schematic side view showing details of the cable compartment in an embodiment of an electrical switchgear according to the present invention;

[0037] Figure 3 This is a first perspective view of an embodiment of a connection device used in an electrical switchgear according to the present invention;

[0038] Figure 4 This is a second perspective view of an embodiment of a connection device used in an electrical switchgear according to the present invention;

[0039] Figure 5 This is a first plan view of an embodiment of a connection device used in an electrical switchgear according to the present invention;

[0040] Figure 6 This is a second plan view of an embodiment of the connection device used in the electrical switchgear according to the present invention;

[0041] Figure 7 This is a third plan view of an embodiment of the connection device used in the electrical switchgear according to the present invention;

[0042] Figure 8 This is a fourth plan view of an embodiment of the connection device used in the electrical switchgear according to the present invention;

[0043] Figure 9This is a fifth plan view of an embodiment of the connection device used in the electrical switchgear according to the present invention;

[0044] Figure 10 This is a sixth plan view of an embodiment of the connection device used in the electrical switchgear according to the present invention. Detailed Implementation

[0045] In the following description, reference will be made to medium-voltage electrical switchgear; however, the present invention more generally relates to low-voltage electrical switchgear and medium-voltage electrical switchgear.

[0046] Please refer to the attached document for details. Figure 1 and Figure 2 In its more general definition, electrical switchgear 100 typically includes a housing 101, which contains one or more main circuit compartments, such as bus compartment 102 accommodating bus system 106 and circuit breaker compartment 103 accommodating circuit breaker 107.

[0047] The electrical switchgear 100 also includes a conductive cable compartment 104, which, for each phase, accommodates one or more cables 108, each cable 108 having a corresponding cable terminal 109. For each phase, a main circuit terminal 110, such as a circuit breaker terminal, is also accommodated inside the cable compartment 104.

[0048] Low-voltage and medium-voltage electrical switchgear are well known in the art and will not be described in further detail.

[0049] Special reference Figure 1 and Figure 2 One of the distinguishing features of the electrical switch cabinet 100 of the present invention is that, for each phase of the circuit, the electrical switch cabinet 100 includes a connection device 1 located in the conductive cable compartment 104 of the electrical switch cabinet 100.

[0050] Reference Figures 3 to 10 The connection device 1 has a central body 2, which is provided with a first connection surface 21, which is adapted to connect to the terminal 110 of the main circuit (e.g., the terminal 110 of the circuit breaker 107 located inside the conductive cable compartment 104).

[0051] The central body 2 of the connecting device 1 is also provided with a second connecting surface 22, which is suitable for connecting to at least the terminal 109 of the conductive cable 108, which is also located inside the conductive cable compartment 104.

[0052] As shown in the attached figure, the central body 2 of the connecting device 1 has a first forming body 3 at one of its longitudinal ends, the first forming body 3 having rounded surfaces 310, 320 protruding outward from the central body 2. The central body 2 of the connecting device 1 also has a second forming body 4 at the longitudinal end opposite to the first forming body 3, the second forming body 4 having rounded surfaces 410, 420 protruding outward from the central body 2.

[0053] In the embodiment shown in the accompanying figures, the central body 2, the first molded body 3, and the second molded body 4 of the connecting device 1 are made as a single piece of conductive material. For example, the central body 2, the first molded body 3, and the second molded body 4 can be integrally made of aluminum or its alloy. Silver-plated aluminum can also be used when specific voltage and / or current ratings are required. In general, the choice of material depends on cost and performance considerations. Furthermore, different embodiments in which the connecting device 1 is made of multiple different parts connected together can also be foreseen, but such embodiments are less advantageous in terms of manufacturing and assembly costs and time.

[0054] The rounded surfaces 310, 320 and 410, 420 of the first molded body 3 and the second molded body 4 can be designed in various ways. For example, the rounded surfaces 310, 320 and 410, 420 of the first molded body 3 and the second molded body 4 can be part of an elliptical surface or a spherical surface, with the former being preferred.

[0055] As shown in the attached figures, in an embodiment of the connection device 1 used in the switch cabinet 100 of the present invention, the central body 2 of the connection device 1 extends along the longitudinal direction x in the xyz reference frame. The central body 2 is defined upward by the xz plane and laterally by first and second parallel planes yz at opposite ends of its longitudinal extension along the x-axis.

[0056] Then, the first molded body 3 includes a first portion 31 protruding above the xz plane, the first portion 31 having a first convex surface 310; similarly, the second molded body 4 includes a first portion 41 protruding above the xz plane, the first portion 41 having a corresponding first convex surface 410. Furthermore, the first molded body 3 includes a second portion 32 located below the xz plane and protruding outward from the first parallel plane yz, the second portion 32 having a second convex surface 320, the second convex surface 320 being rounded to the first convex surface 310 of the corresponding first portion 31 of the first molded body 3.

[0057] Similarly, the second molded body 4 includes a second portion 42 located below the xz plane and protruding outward from the second parallel plane yz in a direction opposite to the second portion 32 of the first molded body 3. The second portion 42 of the second molded body 4 is provided with a second convex surface 420, which is connected to the first convex surface 410 of the corresponding first portion 41 of the second molded body 4 at a rounded corner.

[0058] Therefore, as shown in the attached figures, in this embodiment, the first forming body 3 and the second forming body 4 of the connecting device 1 are located at relative positions to the central body 2 and protrude upward and outward relative to the central body 2. Both the first forming body 3 and the second forming body 4 are provided with continuous rounded surfaces, which are derived from the combination of first convex surfaces 310, 410 and corresponding second convex surfaces 320, 420 (both the first and second convex surfaces form part of an elliptical surface), which improves the uniformity of the electric field around the connecting device 1.

[0059] In the embodiment of the connecting device 1 shown in the attached figures, the first connecting surface 21 of the central body 2 is located in the xz plane, and the second connecting surface 22 of the central body 2 is located substantially perpendicular to the first connecting surface 21 in the xy plane. Other arrangements of the connecting surfaces 21 and 22 on the central body 2 of the connecting device 1 are also feasible, although they are less advantageous in terms of space occupation and insulation effect.

[0060] In an embodiment of the connection device 1 shown in the accompanying figures, the second connection surface 22 of the central body 2 includes a first connection point 210 and a second connection point 220 for connection to terminals 109 of a pair of conductive cables 108. Depending on the requirements and rated voltage and / or current, a single cable connection or multiple cable connections can be anticipated.

[0061] To connect the cable terminal 109 to the connecting device 1, a plurality of holes for inserting fixing components (e.g., screw components) can be provided on the central body 2 of the connecting device 1. In the illustrated embodiment, a pair of holes 211, 212 and 221, 222 are provided corresponding to the first connection point 210 and the second connection point 220 on the central body 2, respectively. In general, depending on the requirements and the rated voltage and / or current, it is foreseeable that there may be a single connection hole or multiple connection holes for each cable terminal 109.

[0062] According to a primary preferred embodiment of the connection device 1 used in the electrical switchgear 100 of the present invention, the first shaped body 3 may advantageously be provided with cut-out portions 51 of its rounded surfaces 310, 320 projecting outward from the central body 2. In the preferred embodiment shown in the accompanying figures, at least a portion 51 of the second convex surface 320 of the second portion 32 of the first shaped body 3 is cut out.

[0063] Similarly, the second molded body 4 may advantageously have cut-out portions 52 of its rounded surfaces 410, 420 projecting outward from the central body 2. In the preferred embodiment shown in the accompanying figures, at least a portion 52 of the second convex surface 420 of the second portion 42 of the second molded body 4 is cut out.

[0064] As noted above, in these embodiments, the first molded body 3 and the second molded body 4 are provided with cut supports 51 and 52 in the corresponding rounded surfaces 310, 320 and 410, 420, respectively, which can accommodate the various pieces of equipment. This is because the rounded surfaces 310, 320 and 410, 420 provide effective equal electric field shielding around the supports 51 and 52 and the entire surrounding area of ​​the various pieces of equipment located in the supports 51 and 52.

[0065] Specifically, in the embodiment shown in the accompanying figures, the first molded body 3 is provided with a support surface for fixing a contact 6 adapted to couple with a corresponding movable contact of a grounding switch (not shown), which may be located in the cable compartment 104. Advantageously, the support surface for fixing the contact 6 is received in a cut-out portion 51 of the second convex surface 320 of the second portion 32 of the first molded body 3.

[0066] Furthermore, the second molded body 4 is advantageously provided with a coupling surface 7, which is adapted to be coupled with a voltage detection device. The coupling surface 7 is conveniently accommodated in the cut-out portion 52 of the second convex surface 420 of the second portion 42 of the second molded body 4.

[0067] Similarly, the second molded body 4 is advantageously also provided with a connection hole 8, which is adapted to receive a connection to a transformer used to draw power to feed auxiliary equipment in the electrical switch cabinet 100. The connection hole 8 is also conveniently accommodated in the cut-out portion 52 of the second convex surface 420 of the second portion 42 of the second molded body 4.

[0068] Therefore, in the embodiment shown in the accompanying figures, the connection device 1 used in the electrical switch cabinet 100 of the present invention is capable of performing a number of additional functions in addition to performing the basic function of connecting the cable terminal 109 to the main circuit terminal 110 of the electrical switch cabinet 100.

[0069] In particular, in the embodiment shown in the attached figures, the connection device 1 used can be used to support the fixed contact 6 of the grounding switch, to provide a signal of voltage presence through the coupling surface 7, to support the connection of the transformer through the connection hole 8, and to provide a balanced electric field that allows overcoming the aforementioned phase-to-phase insulation problem and phase-to-ground insulation problem.

[0070] Moreover, because many functions are integrated into a single device, namely the connection device 1, the solution proposed for the electrical switchgear 100 of the present invention is cheaper and more reliable, thereby allowing for a reduction in the assembly and maintenance time and cost of the switchgear 100.

[0071] Various modifications can be made to the electrical switchgear conceived in this way, all of which fall within the scope of the appended claims. In practice, the materials used, as well as the possible dimensions and shapes, can be any material, size, and shape, depending on the requirements and prior art.

Claims

1. An electrical switch cabinet (100) comprising a housing (101), said housing including at least a main circuit compartment (102; 103) and a conductive cable compartment (104), characterized in that, For each phase of the main circuit, the electrical switch cabinet (100) includes a connection device (1) located in the conductive cable compartment (104), the connection device (1) having a central body (2), the central body (2) having a first connection surface (21) for connection to terminals (110) of the main circuit and a second connection surface (22) for connection to at least terminals (109) of the conductive cable (108), the central body (2) having a first shaped body (3) and a second shaped body (4) at its opposite ends, the first shaped body (3) and the second shaped body (4) each having a rounded surface protruding outward from the central body (2). Wherein, the rounded surfaces of the first molded body (3) and the second molded body (4) are part of an elliptical surface. In the xyz reference frame, the central body (2) of the connecting device (1) extends along the longitudinal direction x and is defined upward by the xz plane and laterally by the first and second parallel planes yz at its opposite ends extending longitudinally. The first molded body (3) and the second molded body (4) each include a first portion (31; 41) protruding above the xz plane and a second portion (32; 42) located below the xz plane and protruding outward from the first and second parallel planes yz, respectively. The first portion has a first convex surface (310; 410), and the second portion has a second convex surface (320; 420). The second convex surface is rounded to the first convex surface (310; 410) of the corresponding first portion (31; 41) of the first molded body (3) and the second molded body (4). The rounded surfaces of the first molded body and the second molded body each include their respective first convex surface and second convex surface. The first connecting surface (21) is located in the xz plane, and the second connecting surface (22) is located in the xy plane and is perpendicular to the first connecting surface (21).

2. The electrical switchgear (100) according to claim 1, characterized in that, The central body (2) of the connecting device (1), as well as the first molded body (3) and the second molded body (4), are made into a single piece.

3. The electrical switchgear (100) according to claim 1 or 2, characterized in that, The second connection surface (22) of the central body (2) includes one or more connection points (210; 220) for connection with one or more conductive cables (108).

4. The electrical switchgear (100) according to claim 1 or 2, characterized in that, In the first molded body (3) and / or the second molded body (4), at least a portion (51; 52) of the rounded surface protruding outward from the central body (2) is cut out.

5. The electrical switchgear (100) according to claim 1 or 2, characterized in that, At least a portion (51; 52) of the second convex surface (320; 420) of the second portion (32; 42) of the first molded body (3) and / or the second molded body (4) is cut out.

6. The electrical switchgear (100) according to claim 4, characterized in that, The first molded body (3) has a support surface for fixing a contact (6) adapted to couple with a corresponding movable contact of a grounding switch located in the conductive cable compartment (104), and the support surface for fixing the contact (6) is accommodated in the cut-out portion (51) of the first molded body (3).

7. The electrical switchgear (100) according to claim 5, characterized in that, The first molded body (3) has a support surface for fixing a contact (6) adapted to couple with a corresponding movable contact of a grounding switch located in the conductive cable compartment (104), and the support surface for fixing the contact (6) is accommodated in the cut-out portion (51) of the first molded body (3).

8. The electrical switchgear (100) according to claim 6 or 7, characterized in that, The second molded body (4) is provided with a coupling surface (7) suitable for coupling with a voltage detection device, the coupling surface (7) being accommodated in the cut-out portion (52) of the second molded body (4).

9. The electrical switchgear (100) according to claim 6 or 7, characterized in that, The second molded body (4) is provided with a connection hole (8) suitable for receiving a transformer connection, the connection hole (8) being accommodated in the cut-out portion (52) of the second molded body (4).

10. The electrical switchgear (100) according to claim 1, characterized in that, The electrical switchgear (100) is a medium-voltage electrical switchgear.

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