Metering cabinet

Abstract

This utility model provides a metering cabinet, including a single-phase measuring unit (100). The single-phase measuring unit includes a sealed gas chamber (10), a voltage transformer (20), and a disconnecting switch (30). The sealed gas chamber is provided with a first conductive element (C1) and a second conductive element (C2). The first and second conductive elements are used to realize cross-wall electrical connection between the inner and outer components of the sealed gas chamber. The second conductive element is used to electrically connect an external cable. The voltage transformer is located outside the sealed gas chamber. The primary terminal of the voltage transformer is electrically connected to the first conductive element. The disconnecting switch is located inside the sealed gas chamber. The disconnecting switch has a moving contact (31) and a stationary contact (32). The moving contact is electrically connected to the first conductive element to electrically connect to the primary terminal of the voltage transformer through the first conductive element. The stationary contact is electrically connected to the second conductive element to electrically connect to an external cable through the second conductive element. This metering cabinet can reduce the difficulty of connecting to the cabinet under test and allows for more flexible relative arrangement of the two cabinets.

Description

Technical Field

[0001] This utility model relates to the field of power transmission and distribution technology, and in particular to metering cabinets. Background Technology

[0002] Current voltage metering in gas-insulated switchgear typically employs a "parallel connection between metering cabinet and the cabinet under test" scheme: a metering cabinet is independently installed on the busbar or feeder side of the cabinet under test, and the connecting bushing of the gas chamber of the metering cabinet is connected to the connecting bushing of the gas chamber of the cabinet under test via a flange-sealing ring to achieve gas conduction and power introduction. This connection method places extremely high demands on the machining accuracy of both cabinets, the levelness of the site foundation, and axial / radial alignment, making the connection quite difficult. Utility Model Content

[0003] The purpose of this utility model is to provide a metering cabinet that can reduce the difficulty of connecting the metering cabinet and the cabinet under test, and shorten the on-site installation cycle.

[0004] This utility model provides a metering cabinet, which includes a single-phase measuring unit. The single-phase measuring unit includes a sealed gas chamber, a voltage transformer, and a disconnecting switch. The sealed gas chamber is provided with a first conductive element and a second conductive element. The first and second conductive elements are used to realize cross-wall electrical connection between the internal and external components of the sealed gas chamber. The second conductive element is used to electrically connect an external cable to the single-phase lead-out terminal of the cabinet under test through the external cable. The voltage transformer is located outside the sealed gas chamber. The primary terminal of the voltage transformer is electrically connected to the first conductive element. The disconnecting switch is located inside the sealed gas chamber. The disconnecting switch has a moving contact and a stationary contact. The moving contact is electrically connected to the first conductive element to electrically connect to the primary terminal of the voltage transformer through the first conductive element. The stationary contact is electrically connected to the second conductive element to electrically connect to the external cable through the second conductive element.

[0005] The metering cabinet can be directly connected to the single-phase lead of the test cabinet via an external cable, which can reduce the difficulty of connecting the metering cabinet and the test cabinet and shorten the on-site installation cycle. In addition, the cable connection allows for more flexible relative arrangement of the metering cabinet and the test cabinet.

[0006] In another illustrative embodiment of the metering cabinet, the sealed gas chamber further includes a first cylinder, a second cylinder, an insulating partition, and a third conductive element. The first cylinder has a first opening and a second opening. The first conductive element is hermetically and insulatedly disposed in the first opening. A disconnect switch is disposed within the second cylinder. The second cylinder has a third opening and a fourth opening. The second conductive element is hermetically and insulatedly disposed in the fourth opening. The insulating partition is hermetically connected between the periphery of the second opening and the periphery of the third opening to electrically isolate the first and second cylinders. The third conductive element passes through the insulating partition. The moving contact and the first conductive element are electrically connected through the third conductive element. This facilitates improved reliability and safety of equipment operation.

[0007] In another illustrative embodiment of the metering cabinet, the first cylinder, the insulating partition, and the second cylinder are arranged sequentially along the height direction of the sealed air chamber. The first opening and the second opening are respectively located on the upper and lower end faces of the first cylinder along the height direction. The third opening and the fourth opening are respectively located on the upper and lower end faces of the second cylinder along the height direction. This design helps to reduce the floor space occupied by the equipment and makes the overall structure more compact.

[0008] In another illustrative embodiment of the metering cabinet, the voltage transformer is disposed on the upper side of the first cylinder along the height direction and fixedly connected to the first cylinder. This makes the overall structure of the equipment more compact and helps to save space.

[0009] In another illustrative embodiment of the metering cabinet, the single-phase measuring unit further includes a first copper busbar and a second copper busbar. The first copper busbar is located inside the first cylinder and one end is electrically connected to a first conductive element. The second copper busbar is located inside the first cylinder and one end is electrically connected to a third conductive element. The other ends of the first copper busbar and the other ends of the second copper busbar are electrically connected in a detachable manner. This facilitates the assembly of the single-phase measuring unit.

[0010] In another illustrative embodiment of the metering cabinet, the surface of the first copper busbar at one end and the surface of the second copper busbar at the other end are electrically bonded. The single-phase measuring unit also includes fasteners. The fasteners detachably connect the overlapping sections of the first and second copper busbars to maintain a tight fit between them. This ensures good conductivity between the first and second copper busbars. The first cylinder has an operating opening opposite the fasteners and includes a cylinder cover for closing the operating opening. This facilitates the installation of the fasteners.

[0011] In another illustrative embodiment of the metering cabinet, the metering cabinet also includes a support frame. The single-phase measuring unit is fixedly connected to the support frame via an insulating partition. This achieves an insulated connection between the single-phase measuring unit and the support frame, which helps improve the reliability and safety of equipment operation.

[0012] In another illustrative embodiment of the metering cabinet, the insulating partition is provided with a through hole connecting the inner cavity of the first cylinder and the inner cavity of the second cylinder. This helps to save on inflation costs.

[0013] In another illustrative embodiment of the metering cabinet, the disconnect switch also includes a grounding contact. The grounding contact is electrically connected to the chamber wall of the sealed gas chamber. This improves the safety performance of the equipment when it is not in use.

[0014] In another illustrative embodiment of the metering cabinet, the metering cabinet is equipped with three single-phase measuring units. The second conductive element of each of the three single-phase measuring units is used to electrically connect to the three-phase leads of the cabinet under test via external cables. This allows the three-phase voltage of the cabinet under test to be detected simultaneously. Attached Figure Description

[0015] The following figures are for illustrative purposes only and do not limit the scope of the present invention.

[0016] Figure 1 This is an exploded perspective view of one illustrative embodiment of the metering cabinet.

[0017] Figure 2 for Figure 1 A partial cross-sectional schematic diagram of the single-phase measurement unit of the metering cabinet shown.

[0018] Figure 3 For illustrative purposes Figure 1 The diagram shows the usage status of the metering cabinet.

[0019] Label Explanation

[0020] 100 Single-phase measurement units

[0021] 10 Sealed gas chamber

[0022] C1 First conductive element

[0023] C2 Second conductive element

[0024] C3 Third conductive element

[0025] 11 First cylinder

[0026] 111 First Opening

[0027] 112 Second opening

[0028] 113 Operating opening

[0029] 114 Cylinder Cap

[0030] P1 First splicing tube

[0031] P2 Second splicing tube

[0032] 12 Second cylinder

[0033] 121 Third opening

[0034] 122 Fourth opening

[0035] P3 Third splicing tube

[0036] P4 Fourth splicing tube

[0037] 13 Insulating partition

[0038] 131 Through Hole

[0039] 20 Voltage Transformers

[0040] 30 Disconnecting switch

[0041] 31 Moving contact

[0042] 32 stationary contacts

[0043] 33 Grounding contact

[0044] 41 First Bronze Bar

[0045] 42 Second Bronze Bar

[0046] 50 Fasteners

[0047] 70 Insulating support

[0048] 80 Conductors

[0049] 90 Grounding Module

[0050] 200 Support Frame

[0051] 300 casing

[0052] 400 test cabinets

[0053] 401 Single-phase gas chamber module

[0054] L Single-phase lead

[0055] 500 external cable

[0056] 600 cable trench

[0057] H (height direction) Detailed Implementation

[0058] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, specific embodiments of the utility model are now described with reference to the accompanying drawings. In the drawings, the same reference numerals indicate unit components with the same or similar structures but the same function.

[0059] In this document, “illustrative” means “serving as an example, illustration or description”, and any illustration or implementation described herein as “illustrative” should not be construed as a more preferred or advantageous technical solution.

[0060] In this document, terms such as "first," "second," etc., do not indicate degree of importance or order, but are used only to distinguish them from each other for the purpose of document description. Nouns and pronouns relating to persons in this patent application are not limited to specific genders.

[0061] To keep the drawings simple, each drawing only schematically shows the unit components related to this utility model, and they do not represent the actual structure of the product.

[0062] Figure 1This is an exploded perspective view illustrating one embodiment of a metering cabinet. This metering cabinet is used, for example, to meter the voltage on the bus or feeder side of a gas-insulated switchgear, but is not limited thereto. Figure 1 As shown, the metering cabinet of this illustrative embodiment includes a support frame 200, a housing 300, and three single-phase measuring units 100. To illustrate the internal structure of the metering cabinet, Figure 1 The outer casing 300 is disassembled. The support frame 200 supports the single-phase measurement unit 100. The outer casing 300 covers the support frame 200 and the single-phase measurement unit 100 to provide protection and isolation. Furthermore, the user interface of the metering cabinet is integrated into the surface of the outer casing 300. Each single-phase measurement unit 100 is used to measure the voltage of a single-phase busbar or feeder of the cabinet under test.

[0063] Figure 2 for Figure 1 A partial cross-sectional view of the single-phase measurement unit of the metering cabinet shown. Figure 2 As shown, each single-phase measuring unit 100 includes a sealed gas chamber 10, a voltage transformer 20, and a disconnecting switch 30. In use, the sealed gas chamber 10 is sealed and filled with an insulating gas, such as, but not limited to, SF6 (sulfur hexafluoride) and clean gas, thereby reducing the break distance under the same withstand voltage requirements.

[0064] like Figure 2 As shown, the sealed gas chamber 10 is equipped with a first conductive element C1 and a second conductive element C2. The first conductive element C1 and the second conductive element C2 are used to achieve cross-wall electrical connection between the internal and external components of the sealed gas chamber 10. The second conductive element C2 is used to electrically connect an external cable to the single-phase lead-out terminal of the cabinet under test via the external cable. The single-phase lead-out terminal can be a single-phase lead-out terminal on the busbar side or a single-phase lead-out terminal on the feeder side. The voltage transformer 20 is located outside the sealed gas chamber 10. The primary terminal of the voltage transformer 20 is electrically connected to the first conductive element C1.

[0065] The disconnector switch 30 is located within the sealed gas chamber 10. The disconnector switch 30 has a moving contact 31 and a stationary contact 32. The moving contact 31 is electrically connected to a first conductive element C1, thereby connecting to the primary terminal of the voltage transformer 20. The stationary contact 32 is electrically connected to a second conductive element C2, thereby connecting to an external cable. Specifically, in this illustrative embodiment, the moving contact 31 is indirectly connected to the first conductive element C1, for example, via a first copper busbar 41, a second copper busbar 42, and a third conductive element C3; the stationary contact 32 is indirectly connected to the second conductive element C2, for example, via a conductor 80, which is, for example, a conductive rod, but is not limited thereto. In other illustrative embodiments, the moving contact 31 and the first conductive element C1, and the stationary contact 32 and the second conductive element C2, may also be directly electrically connected, for example.

[0066] Figure 3 For illustrative purposes Figure 1 The diagram shows the usage status of the metering cabinet. The left side of the diagram represents the test cabinet 400, and the right side represents the metering cabinet. Only one single-phase measurement unit 100 of the metering cabinet and one single-phase gas chamber module 401 of the test cabinet 400 are visible in the diagram. Figure 3 As shown, when in use, the metering cabinet is connected, for example, to the second conductive element C2 of each single-phase measuring unit 100 and the single-phase lead-out terminal L of each single-phase gas chamber module 401 of the test cabinet 400 via an external cable 500. The external cable 500 is laid in a cable trench 600, for example, but is not limited thereto. When the moving contact 31 and the stationary contact 32 of the disconnecting switch 30 are closed, the primary terminal of the voltage transformer 20 is electrically connected to the single-phase lead-out terminal L of the test cabinet 400, thereby realizing voltage metering. When the moving contact 31 and the stationary contact 32 of the disconnecting switch 30 are disconnected, the electrical circuit between the primary terminal of the voltage transformer 20 and the single-phase lead-out terminal L of the test cabinet 400 is cut off.

[0067] The metering cabinet can be directly connected to the single-phase output terminal of the test cabinet via an external cable 500, reducing the connection difficulty and shortening the on-site installation cycle. Furthermore, the cable connection allows for more flexible relative placement of the metering cabinet and the test cabinet. In addition, since the metering cabinet and the test cabinet are two independent cabinets, they can be connected via the external cable 500, the length of which can be adjusted according to actual needs, thus allowing for unrestricted spacing between them. Moreover, the metering cabinet can be connected to any test cabinet on-site, offering considerable flexibility. Furthermore, users can purchase the metering cabinet separately to connect to their own test cabinet.

[0068] In other illustrative embodiments, the number of single-phase measurement units 100 in the metering cabinet can be configured as needed. If only one set is provided, it constitutes a single-phase metering cabinet.

[0069] Specifically, such as Figure 2 As shown in the schematic embodiment, the sealed air chamber 10 further includes a first cylinder 11, a second cylinder 12, an insulating partition 13, and a third conductive element C3. The first cylinder 11 has a first opening 111 and a second opening 112. The first conductive element C1 is hermetically and insulatingly disposed in the first opening 111, thereby maintaining the sealed air chamber 10 while electrically isolating the first cylinder 11 from the first conductive element C1. A disconnect switch 30 is disposed within the second cylinder 12. A stationary contact 32 is indirectly fixed to the second cylinder 12, for example, via an insulating support 70. Figure 2 The insulating support 70 on the right side is mounted between the front and rear inner walls of the second cylinder 12, thereby achieving electrical insulation between the stationary contact 32 and the second cylinder 12.

[0070] The second cylinder 12 has a third opening 121 and a fourth opening 122. A second conductive element C2 is hermetically and insulatedly disposed in the fourth opening 122, thereby maintaining the airtightness of the sealed chamber 10 while electrically isolating the second cylinder 12 from the second conductive element C2. An insulating partition 13 is hermetically connected between the periphery of the second opening 112 and the periphery of the third opening 121, thereby maintaining the airtightness of the sealed chamber 10 while electrically isolating the first cylinder 11 and the second cylinder 12. The insulating partition 13 may be made of resin, but is not limited thereto. A third conductive element C3 passes through the insulating partition 13. The moving contact 31 and the first conductive element C1 are electrically connected through the third conductive element C3. This improves the reliability and safety of equipment operation.

[0071] like Figure 2 As shown in this illustrative embodiment, the first cylinder 11, the insulating partition 13, and the second cylinder 12 are arranged sequentially along the height direction H of the sealed air chamber 10. The first opening 111 and the second opening 112 are respectively located on the upper and lower end faces of the first cylinder 11 along the height direction H. The third opening 121 and the fourth opening 122 are respectively located on the upper and lower end faces of the second cylinder 12 along the height direction H. In use, the metering cabinet is placed, for example, at an angle where the height direction H of the sealed air chamber 10 is in the same direction as the direction of gravity. This helps to reduce the floor space occupied by the equipment and makes the overall structure more compact.

[0072] like Figure 2 As shown in the schematic embodiment, the voltage transformer 20 is disposed on the upper side of the first cylinder 11 along the height direction H and is fixedly connected to the first cylinder 11. This makes the overall structure of the equipment more compact and helps to save space.

[0073] Furthermore, such as Figure 2 As shown in this illustrative embodiment, the first cylindrical body 11 is, for example, composed of a first splicing cylinder P1 and a second splicing cylinder P2 sequentially spliced ​​along the height direction H. A first opening 111 is provided in the first splicing cylinder P1, and a second opening 112 is provided in the second splicing cylinder P2. The second cylindrical body 12 is, for example, composed of a third splicing cylinder P3 and a fourth splicing cylinder P4 sequentially spliced ​​along the height direction H. A third opening 121 is provided in the third splicing cylinder P3, and a fourth opening 122 is provided in the fourth splicing cylinder P4. The first splicing cylinder P1, the second splicing cylinder P2, the third splicing cylinder P3, and the fourth splicing cylinder P4 are, for example, existing standard modules, which helps to save development costs. In other illustrative embodiments, the first cylindrical body 11 and the second cylindrical body 12 can also be spliced ​​from more splicing cylinders, or the first cylindrical body 11 can be a one-piece molded component, and the second cylindrical body 12 can also be a one-piece molded component.

[0074] like Figure 2As shown in the schematic embodiment, the single-phase measuring unit 100 further includes a first copper busbar 41 and a second copper busbar 42. The first copper busbar 41 is located inside the first cylindrical body 11 and its upper end is electrically connected to a first conductive element C1. The second copper busbar 42 is located inside the first cylindrical body 11 and its lower end is electrically connected to a third conductive element C3. The lower end of the first copper busbar 41 and the upper end of the second copper busbar 42 are electrically connected in a separable manner.

[0075] Specifically, such as Figure 2 As shown, in this illustrative embodiment, the lower end of the first copper busbar 41 and the upper end of the second copper busbar 42 are electrically bonded together. The single-phase measuring unit 100 also includes a fastener 50. The fastener 50 is detachably connected to the overlapping section of the first copper busbar 41 and the second copper busbar 42 to maintain a tight fit between them, thereby ensuring good conductivity between the first copper busbar 41 and the second copper busbar 42. The fastener 50 is, for example, a bolted connection pair, but is not limited thereto. The first cylinder 11 has an operating opening 113 opposite to the fastener 50 and is provided with a cylinder cover 114 for closing the operating opening 113. This facilitates the installation of the fastener. Specifically, in this illustrative embodiment, the operating opening 113 is provided in the second splicing cylinder P2.

[0076] During the assembly of the single-phase measuring unit 100, for example, the first cylinder 11, the first conductive element C1, the voltage transformer 20, and the first copper busbar 41 can be assembled together and then mounted as a whole on the insulating partition 13 on which the third conductive element C3 and the second copper busbar 42 are installed, and then the first copper busbar 41 and the second copper busbar 42 are connected. Alternatively, the first splicing cylinder P1, the first conductive element C1, the voltage transformer 20, and the first copper busbar 41 can be assembled together and then mounted as a whole on the second splicing cylinder P2 on which the insulating partition 13, the third conductive element C3, and the second copper busbar 42 are installed, and then the first copper busbar 41 and the second copper busbar 42 are connected. This facilitates the assembly of the single-phase measuring unit 100.

[0077] like Figure 1 and Figure 3 As shown in the schematic embodiment, the single-phase measuring unit 100 is fixedly connected to the support frame 200 via an insulating partition 13. This achieves an insulated connection between the single-phase measuring unit 100 and the support frame 200, which helps improve the reliability and safety of equipment operation.

[0078] In an illustrative embodiment, the insulating partition 13 is provided with a through hole 131 connecting the inner cavity of the first cylinder 11 and the inner cavity of the second cylinder 12. This allows the first cylinder 11 and the second cylinder 12 to be inflated simultaneously, saving on inflation costs, but this is not a limitation. In other illustrative embodiments, the insulating partition 13 may not have a through hole, and the inner cavities of the first cylinder 11 and the second cylinder 12 may be isolated from each other, requiring separate inflation for each.

[0079] like Figure 2 As shown in the illustrative embodiment, the disconnecting switch 30 also includes a grounding contact 33, meaning the disconnecting switch 30 is a three-position disconnecting switch. The grounding contact 33 is electrically connected to the wall of the sealed gas chamber 10. Specifically, in this illustrative embodiment, the grounding contact 33 is electrically connected to the inner wall of the second cylinder 12. In use, the second cylinder 12 is kept in a grounded state, for example. When the moving contact 31 of the disconnecting switch 30 is closed with the grounding contact 33, the primary circuit of the voltage transformer 20 can be grounded, thereby improving the safety performance of the equipment when it is not in use.

[0080] In use, the first cylinder 11 is also kept in a grounded state, for example. Specifically, the single-phase measurement unit 100 also includes, for example, a grounding module 90, which is electrically connected to the support frame 200 to achieve grounding through the support frame 200. The grounding module 90 is electrically connected to the first cylinder 11 and the second cylinder 12, thereby grounding the first cylinder 11 and the second cylinder 12. This helps to improve the safety performance of the equipment.

[0081] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0082] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present utility model, and are not intended to limit the scope of protection of the present utility model. All equivalent implementation schemes or modifications made without departing from the spirit of the present utility model, such as combinations, divisions or repetitions of features, should be included within the scope of protection of the present utility model.

Claims

1. A metering cabinet, characterized in that, Includes a single-phase measurement unit (100), said single-phase measurement unit (100) comprising: A sealed air chamber (10) is provided with a first conductive element (C1) and a second conductive element (C2). The first conductive element (C1) and the second conductive element (C2) are used to realize the cross-wall electrical connection between the inner and outer components of the sealed air chamber (10). The second conductive element (C2) is used to electrically connect an external cable to connect the single-phase lead-out terminal of the cabinet under test through the external cable. A voltage transformer (20), located outside the sealed gas chamber (10), has its primary terminals electrically connected to the first conductive element (C1); and A disconnector (30) is located inside the sealed gas chamber (10). The disconnector (30) has a moving contact (31) and a stationary contact (32). The moving contact (31) is electrically connected to the first conductive element (C1) to electrically connect to the primary terminal of the voltage transformer (20) through the first conductive element (C1). The stationary contact (32) is electrically connected to the second conductive element (C2) to electrically connect to an external cable through the second conductive element (C2).

2. The metering cabinet as described in claim 1, characterized in that, The sealed air chamber (10) further includes: The first cylindrical body (11) has a first opening (111) and a second opening (112), and the first conductive element (C1) is airtightly and insulatedly disposed in the first opening (111). The second cylinder (12) has the isolating switch (30) disposed inside the second cylinder (12). The second cylinder (12) has a third opening (121) and a fourth opening (122). The second conductive element (C2) is disposed in the fourth opening (122) in an airtight and insulating manner. An insulating partition (13), hermetically connected between the periphery of the second opening (112) and the periphery of the third opening (121), electrically isolates the first cylinder (11) and the second cylinder (12); and A third conductive element (C3) is disposed through the insulating partition (13), and the moving contact (31) and the first conductive element (C1) are electrically connected through the third conductive element (C3).

3. The metering cabinet as described in claim 2, characterized in that, The first cylinder (11), the insulating partition (13), and the second cylinder (12) are arranged sequentially along the height direction (H) of the sealed air chamber (10). The first opening (111) and the second opening (112) are respectively located on the upper and lower end faces of the first cylinder (11) along the height direction (H). The third opening (121) and the fourth opening (122) are respectively located on the upper and lower end faces of the second cylinder (12) along the height direction (H).

4. The metering cabinet as described in claim 3, characterized in that, The voltage transformer (20) is disposed on the upper side of the first cylinder (11) along the height direction (H) and is fixedly connected to the first cylinder (11).

5. The metering cabinet as described in claim 2, characterized in that, The single-phase measurement unit (100) also includes: A first copper busbar (41) is located inside the first cylinder (11) and one end is electrically connected to the first conductive element (C1); and The second copper busbar (42) is located inside the first cylinder (11) and one end is electrically connected to the third conductive element (C3). The other end of the first copper busbar (41) and the other end of the second copper busbar (42) are electrically connected in a separable manner.

6. The metering cabinet as described in claim 5, characterized in that, The surface of the first copper busbar (41) and the surface of the second copper busbar (42) are electrically bonded together. The single-phase measuring unit (100) also includes a fastener (50) that is detachably connected to the overlapping section of the first copper busbar (41) and the second copper busbar (42) to keep them tightly bonded. The first cylinder (11) has an operating opening (113) opposite to the fastener (50) and includes a cylinder cover (114) for closing the operating opening (113).

7. The metering cabinet as described in claim 2, characterized in that, The metering cabinet also includes a support frame (200), and the single-phase measuring unit (100) is fixedly connected to the support frame (200) through the insulating partition (13).

8. The metering cabinet as described in claim 2, characterized in that, The insulating partition (13) is provided with a through hole (131) that connects the inner cavity of the first cylinder (11) and the inner cavity of the second cylinder (12).

9. The metering cabinet as described in claim 1, characterized in that, The disconnector switch (30) also includes a grounding contact (33) which is electrically connected to the chamber wall of the sealed chamber (10).

10. The metering cabinet as described in claim 1, characterized in that, The metering cabinet is equipped with three single-phase measurement units (100), and the second conductive element (C2) of the three single-phase measurement units (100) is used to electrically connect to the three-phase lead-out terminals of the cabinet under test through external cables.

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