Current transformer and switch cabinet

Abstract

The utility model provides a current transformer and a switch cabinet, the current transformer comprises a housing (1), the housing (1) is provided with a first surface (11) and a second surface (12), the first surface (11) is adjacent to the second surface (12); the inner conductor is positioned in the shell (1); the wire inlet terminal (2) is connected to the internal conductor and exposed out of the first surface (11), and the wire inlet terminal (2) is used for being connected to a static contact (81) of the circuit breaker; and the conducting bar (3) is connected to the inner conductor and extends out of the second surface (12), and the conducting bar (3) is parallel to the first surface (11).

Description

Technical Field

[0001] This utility model relates to the field of power systems, and in particular to a current transformer and switchgear. Background Technology

[0002] Switchgear is a crucial piece of equipment in power systems. To ensure its safe operation, its operational status must be monitored and measured.

[0003] The primary function of a current transformer (CT) is to measure current, helping operators understand the current status of the switchgear in real time and thus take timely measures to ensure the safe operation of the power system. CTs are typically installed in the cable compartment of the switchgear and connected to the stationary contacts of the circuit breaker.

[0004] In the existing technology, the lower branch line is connected by the stationary contact, and then the CT is connected by the lower branch line. There are too many overlapping surfaces, which will cause phase-to-phase insulation problems. Utility Model Content

[0005] In view of this, the present invention proposes a current transformer, comprising:

[0006] A housing having a first surface and a second surface, the first surface and the second surface being adjacent to each other;

[0007] An internal conductor located within the housing;

[0008] An incoming terminal, which is connected to the internal conductor and exposed from the first surface, is used to connect to the stationary contact of the circuit breaker;

[0009] A conductive busbar is connected to the internal conductor and extends from the second surface, the conductive busbar being parallel to the first surface.

[0010] By placing the input terminals and conductor busbars of the current transformer on two adjacent surfaces, the input terminals can be directly connected to the stationary contact, thereby reducing the overlap caused by the use of branch conductor busbars and ensuring phase-to-phase insulation.

[0011] Optionally, the incoming terminal and the stationary contact are integrally formed in the current transformer described above. This not only simplifies the process but also reduces heat dissipation.

[0012] Optionally, the current transformer described above may further include: an insulating cylinder extending from the first surface, wherein both the incoming terminal and the stationary contact are cylindrical, the incoming terminal is located within the insulating cylinder, and at least a portion of the stationary contact protrudes from the insulating cylinder, the insulating cylinder being integrally formed with the housing. This insulating cylinder provides a certain degree of support and also facilitates phase-to-phase insulation.

[0013] Optionally, the current transformer described above may also include:

[0014] Two insulating plates, perpendicular to the second surface and distributed on both sides of the conductive busbar; or

[0015] The bottom surface of the U-shaped insulating plate is fixed to the second surface.

[0016] According to the current transformer described above, optionally, the housing is used to fix it on the fixing plate, and the current transformer also includes secondary terminals and a skirt structure;

[0017] The secondary wiring terminal is located on the third surface of the housing, and the third surface is disposed opposite to the first surface. Therefore, the umbrella skirt structure includes at least one of the following structures:

[0018] The umbrella skirt structure includes a plurality of first horizontal plates located on the first surface and perpendicular to the first surface, and the umbrella skirt structure is located between the incoming terminal and the fixing plate;

[0019] The umbrella skirt structure includes two first vertical plates located on the second surface and perpendicular to the second surface, which are distributed on both sides of the conductive busbar;

[0020] or

[0021] The secondary wiring terminal is located on the second surface. The umbrella skirt structure includes two second vertical plates and several second horizontal plates, wherein the two second vertical plates are perpendicular to the first surface and distributed on both sides of the incoming terminal, and the second horizontal plates are located between the secondary wiring terminal and the conductive bar.

[0022] According to the current transformer described above, optionally, the length of the first horizontal plate protruding from the first surface is greater than the length of the incoming terminal protruding from the first surface, so that the creepage distance between the stationary contact and the fixing plate to which the current transformer is fixed can be maximized; or, the length of the first horizontal plate protruding from the first surface is equal to the length of the incoming terminal protruding from the first surface. This can prevent the first horizontal plate from affecting the heat dissipation of the stationary contact.

[0023] According to the current transformer described above, optionally, the input terminal is a copper busbar, and the stationary contact includes a tubular body and a flat end connected to the tubular body, and the input terminal is used to connect to the flat end.

[0024] According to the current transformer described above, optionally, the housing is a cube, and at least one set of adjacent surfaces in the housing has a transition section. This facilitates demolding.

[0025] Optionally, according to the current transformer described above, the first surface is perpendicular to the second surface.

[0026] This utility model also provides a switch cabinet, including a current transformer and a circuit breaker as described in any of the preceding claims. Attached Figure Description

[0027] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can more clearly understand the above and other features and advantages of the present invention, in which:

[0028] Figure 1 This is a schematic diagram of the structure of a current transformer according to an embodiment of the present invention.

[0029] Figure 2 for Figure 1 A schematic diagram of the current transformer from another angle.

[0030] Figure 3 This is a schematic diagram of the structure of a current transformer according to another embodiment of the present invention.

[0031] Figure 4 This is a schematic diagram of the structure of a current transformer according to another embodiment of the present invention.

[0032] Figure 5 This is a schematic diagram of the structure of a current transformer according to another embodiment of the present invention.

[0033] Figure 6 This is a partial structural diagram of the cable compartment of the switchgear according to the present invention.

[0034] The reference numerals in the attached figures are as follows:

[0035] 1-Shell

[0036] 11-First Surface

[0037] 12-Second Surface

[0038] 121-Fixing Hole

[0039] 13-Third Surface

[0040] 14-Transition Section

[0041] 2-Incoming terminal

[0042] 3-Conducting busbar

[0043] 4-Insulating cylinder

[0044] 51-Insulation Board

[0045] 52-U-shaped insulation board

[0046] 61-First horizontal board

[0047] 62-First vertical board

[0048] 63-Second Horizontal Board

[0049] 64-Second vertical board

[0050] 71-Fixing Plate

[0051] 72-Secondary Terminal Block

[0052] 81-Stationary contacts of circuit breaker

[0053] 91-Stationary contact of grounding switch

[0054] 92-Support Insulator

[0055] 93-Framework

[0056] 94-Conductive components

[0057] 95-Cable compartment roof Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this utility model clearer, the following embodiments are provided to further illustrate this utility model in detail. The nouns and pronouns referring to "person" in this patent application are not limited to specific genders.

[0059] This utility model provides a current transformer that can be directly connected to the stationary contact, reducing the contact area. Generally, a circuit breaker has three phases, each phase having one stationary contact and one moving contact, and correspondingly, each phase has a current transformer. Typically, the stationary contacts 81 of the circuit breaker are arranged side-by-side, such as... Figure 6 As shown, current transformers are also arranged side by side, and each current transformer must be phase-to-phase insulated from the next.

[0060] like Figures 1 to 6 As shown, the current transformer includes a housing 1, an internal conductor, an input terminal 2, and a conductor bar 3.

[0061] The housing 1 has a first surface 11 and a second surface 12, which are adjacent to each other. For example, the first surface 11 and the second surface 12 are two adjacent surfaces that are perpendicular to each other. This arrangement facilitates the connection of the incoming terminal 2 and the conductive bus 3 mounted thereon to other components. The housing 1 can be made of an insulating material, such as epoxy resin. As an example, the housing 1 can be a cube with six surfaces: four side surfaces, one top surface, and one bottom surface. For easy demolding, the housing 1 has a transition portion 14 between at least one set of adjacent surfaces. Figures 1 to 5 As shown, there is a transition section 14 between any two adjacent sides of the four sides, and there are also transition sections 14 between the side and the bottom surface, and between the side and the top surface. Figures 1 to 5 As can be seen, there is no transition portion 14 between the two sides with smaller surface areas and the bottom or top surface. Due to the smaller surface area, the resistance encountered during demolding is smaller, so the transition portion 14 can be omitted. In addition, the presence of the transition portion 14 makes the positions where two adjacent current transformers are prone to discharge as far apart as possible, thereby minimizing the creepage effect between them.

[0062] An internal conductor (not shown in the figure) is located inside the housing 1 and is used to connect the incoming terminal 2 and the conductor bar 3 to form a circuit. This internal conductor may include multiple components to realize the function of a current transformer; the specific structure is prior art and will not be described in detail here.

[0063] The input terminal 2 is connected to the internal conductor and protrudes from the first surface 11. The input terminal 2 is used to connect to the stationary contact 81 of the circuit breaker. The stationary contact 81 is located in the same phase as the current transformer. As an example, most of the input terminal 2 is located within the housing 1, with a small portion protruding from the first surface 11 for connecting to the stationary contact 81. This protrusion can be understood as the input terminal 2 being visible when facing the first surface 11. Figure 3 and Figure 5 The diagram shows the case where only a small portion of the input terminal 2 protrudes from the first surface 11, allowing for better connection to the stationary contact. Of course, the length of the input terminal 2 protruding from the first surface 11 can be selected according to actual needs, for example... Figure 4 As an example, the input terminal 2 is integrally formed with at least a portion of the internal conductor, thus reducing assembly steps and simplifying the process. As another example, such as... Figure 1 and Figure 2 As shown, the incoming terminal can also be integrally formed with the stationary contact 81, which not only simplifies the process but also reduces heat dissipation. Figure 1 and Figure 2The portion of the input terminal 2 is not shown. More specifically, a portion of the internal conductor, the input terminal 2, and the stationary contact 81 are integrally formed. The integrally formed portion is, for example, a cylinder, which can be solid or hollow. More specifically, a portion of the internal conductor and the input terminal 2 are conductive rods or tubular bodies, and the stationary contact 81 is a tubular body. This not only facilitates assembly but also provides better heat dissipation performance for the stationary contact 81. Figure 1 and Figure 2 The diagram shows the case where the input terminal 2 and the stationary contact 81 are integrally formed. The portion connecting the input terminal 2 and the internal conductor is not shown. The input terminal 2 and the internal conductor can also be integrally formed. The input terminal 2 has a screw hole, and the stationary contact 81 is screwed to it. If the input terminal 2 is a tubular body, its end is closed and has a screw hole. If the input terminal 2 is a conductive rod, a screw hole can be directly provided on its end face. In this way, the stationary contact 81 can be connected to the input terminal 2 through the screw hole, a simple and quick connection method. Alternatively, a portion of the internal conductor can be cylindrical, the input terminal 2 can be a copper busbar, and the stationary contact 81 can include a tubular body and a flat end connected to the tubular body (not shown in the diagram), with the input terminal 2 used to connect to the flat end.

[0064] The conductive busbar 3 is connected to the internal conductor and extends from the second surface 12, parallel to the first surface 11. Specifically, the conductive busbar 3 can be a copper busbar. This conductive busbar 3 serves as an outgoing terminal. It is used to connect external devices, such as a grounding switch via a conductive element 94. Figure 6 As shown, the conductive component 94 is also a copper busbar, or the conductive busbar 3 is connected to a copper busbar in the cable or switch cabinet's backpack. Figures 1 to 6 As shown, the conductive busbar 3 is parallel to the first surface 11. This arrangement is highly versatile, for example, it is suitable for narrow cabinet types and facilitates connection to the copper busbars in the busbar compartment of the current switchgear.

[0065] The stationary contact 81 of the circuit breaker can be a conductive rod or a conductive tube, and the material can be copper. The stationary contact 81 can be provided with parallel heat dissipation holes. Specific details are omitted. Furthermore, the end of the stationary contact 81 away from the housing 1 has rounded corners to reduce the possibility of tip discharge.

[0066] In this way, by placing the current transformer’s input terminal 2 and the conductor bus 3 on two adjacent surfaces, the input terminal 2 can be directly connected to the stationary contact 81, thereby reducing the overlap caused by the use of branch conductor bus and ensuring phase-to-phase insulation.

[0067] As an example, such as Figure 1 and Figure 2As shown, the current transformer may further include an insulating cylinder 4 extending from the first surface 11. Both the incoming terminal and the stationary contact 81 are cylindrical. The incoming terminal is located within the insulating cylinder 4, and at least a portion of the stationary contact 81 protrudes from the insulating cylinder 4. The insulating cylinder 4 is integrally formed with the housing 1. The insulating cylinder 4 provides a certain supporting force and also facilitates phase-to-phase insulation. Specifically, the housing 1 and the insulating cylinder 4 are integrally cast.

[0068] As an example, to improve interphase insulation, insulating components can be installed on both sides of the conductor bus 3. For example, such as... Figure 3 and Figure 4 As shown, two insulating plates 51 are perpendicular to the second surface 12 and distributed on both sides of the conductive bar 3. These insulating plates 51 can be integrally formed with the housing 1, specifically using a casting process. This reduces the steps of installing the insulating cover and simplifies the assembly process. The length of these two insulating plates 51 needs to be sufficiently long; their length in the direction perpendicular to the second surface 12 must be greater than that of the second conductive bar 3 to achieve the insulating function. Alternatively, a U-shaped insulating plate 52 can be provided on the current transformer, such as... Figure 6 As shown, the bottom surface of the U-shaped insulating plate 52 is fixed to the second surface 12. Specifically, the U-shaped insulating plate 52 can be fixed to the second surface 12 by means of a fixing hole 121 on the second surface 12, through which a fixing member (not shown in the figure) passes through the fixing hole 121 and the U-shaped insulating plate 52. Whether to add the U-shaped insulating plate 52 can be selected according to actual needs.

[0069] As another example, the housing 1 of the current transformer is used to fix it to the mounting plate 71. The current transformer also includes secondary terminals 72 and a skirt structure. The mounting plate 71 here can be a single mounting plate 71, which is fixed to the current transformer, such as... Figures 1 to 4 As shown, the fixing plate 71 is fixed to the fourth surface of the current transformer, which is disposed opposite to the second surface 12, or as... Figure 5 As shown, the fixing plate 71 is fixed to the third surface 13 of the current transformer, and the current transformer can be fixed to the switch cabinet through the fixing plate 71; or, the fixing plate 71 is part of the frame 93 of the switch cabinet, such as the side wall or top plate of the cable compartment. The secondary terminal 72 here is used to monitor the online current, and it can calculate the current of the primary circuit through the induced current in the circuit formed by the incoming terminal 2 and the conductor 3. The third surface here is arranged opposite to the first surface 11. The fixing plate 71 can avoid the secondary terminal 72. Of course, a separate fixing plate 71 can also be used instead of the current transformer, and the entire current transformer can be fixed in the switch cabinet. In this case, the plate on which the current transformer is fixed to the switch cabinet can also be regarded as a fixing plate.

[0070] The location of the current transformer fixed in the cable compartment will affect the position of the secondary terminal 72 and the shed structure. The following example illustrates this:

[0071] Example 1: Figures 1 to 4 As shown, the secondary terminal 72 is located on the third surface 13 of the housing 1, and the third surface 13 is disposed opposite to the first surface 11. Therefore, the umbrella skirt structure includes at least one of the following structures:

[0072] The umbrella skirt structure includes several first horizontal plates 61 located on the first surface 11 and perpendicular to the first surface 11. The umbrella skirt structure is located between the inlet terminal 2 and the fixing plate 71.

[0073] The umbrella skirt structure includes two first vertical plates 62 located on and perpendicular to the second surface 12, which are distributed on both sides of the conductive busbar 3.

[0074] Several first horizontal plates 61 on the first surface 11 can increase the creepage distance to ground and to the secondary wiring position. The number of first horizontal plates 61 can be set according to actual needs. Figures 1 to 2 The two first vertical plates 62 in the middle mainly function as umbrella skirts to increase the creepage distance. Figure 3 and Figure 4 Since an insulating plate 51 is provided on the second surface 12, there is no need to separately provide a first vertical plate 61. Figure 1 and Figure 2 As can be seen, the length of the first vertical plate 62 extending out of the second surface 12 is less than the length of the conductive busbar 3 extending out of the second surface 12.

[0075] Example 2:

[0076] like Figure 5 As shown, the secondary terminal 72 is located on the second surface 12. The umbrella-shaped structure includes two second vertical plates 64 and several second horizontal plates 63. The two second vertical plates 64 are perpendicular to the first surface 11 and distributed on both sides of the incoming terminal 2. The second horizontal plates 63 are located between the secondary terminal 72 and the conductive busbar 3. The two second vertical plates 64 on the first surface 11 mainly serve to increase the creepage distance to ground and the phase-to-phase clearance. Adding several second horizontal plates 63 to the second surface 12 can increase the creepage distance to the secondary wiring position. By placing the secondary terminal 72 on the second surface 12, the third surface 13 of the current transformer can be fixed in the cable compartment, achieving side mounting. The third surface 13 is arranged opposite to the first surface 11.

[0077] More specifically, the first horizontal plate 61 located on the first surface 11 protrudes beyond the first surface 11 by a greater length than the length of the incoming terminal 2 protruding beyond the first surface 11. This maximizes the creepage distance between the stationary contact 81 and the mounting plate 71 on which the current transformer is fixed. Or, as... Figures 1 to 4 As shown, the length of the first horizontal plate 61 protruding from the first surface 11 is equal to the length of the incoming terminal 2 protruding from the first surface 11. This can prevent the first horizontal plate 61 from affecting the heat dissipation of the stationary contact 81.

[0078] This utility model also provides a switch cabinet, which includes a current transformer and a circuit breaker as described in any of the foregoing examples. The current transformer can be installed at the top of the cable compartment, such as... Figure 6 As shown, it is fixed to the top plate 95 of the cable compartment. This current transformer can also be installed on the side wall of the cable compartment, depending on actual needs. Figure 6 Part of the structure inside the cable compartment is shown. Figure 6 The current transformer shown is Figure 1 The structure of the current transformer shown is illustrated.

[0079] like Figure 4 As shown, the switch cabinet also includes a grounding switch. The conductive busbar 3 is connected to the grounding switch via a conductive element 94, specifically to the stationary contact 91 of the grounding switch. The stationary contact 81 is fixed to a supporting insulator 92, which is fixed to the frame 93. The conductive element 94 here is, for example, a copper busbar.

[0080] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A current transformer, characterized by The utility model relates to a current transformer, comprising: a housing (1) having a first surface (11) and a second surface (12) adjacent to each other; an internal conductor located in the housing (1); a line terminal (2) connected to the internal conductor and exposed from the first surface (11), the line terminal (2) being used for connecting to a static contact (81) of a circuit breaker; a conductive bar (3) connected to the internal conductor and extending from the second surface (12), the conductive bar (3) being parallel to the first surface (11).

2. The current transformer of claim 1, wherein, The line terminal (2) is integrally formed with the static contact (81).

3. The current transformer of claim 2, wherein, Further comprising: an insulating cylinder (4) extending from the first surface (11), the line terminal (2) and the static contact (81) being cylindrical, the line terminal (2) being located in the insulating cylinder (4) and at least a part of the static contact (81) being exposed from the insulating cylinder (4), the insulating cylinder (4) being integrally formed with the housing (1).

4. The current transformer of claim 1, wherein, Further comprising: two insulating plates (51) perpendicular to the second surface (12) and distributed on both sides of the conductive bar (3); or a U-shaped insulating plate (52) having a bottom surface fixed to the second surface (12).

5. The current transformer of claim 1, wherein, The housing (1) is used for being fixed on a fixing plate (71), and the current transformer further comprises a secondary wiring terminal (72) and a shed structure; The secondary wiring terminal (72) is located on a third surface (13) of the housing (1), the third surface (13) being oppositely arranged to the first surface (11), and the shed structure comprises at least one of the following structures: The shed structure comprises a plurality of first horizontal plates (61) located on the first surface (11) and perpendicular to the first surface (11), the shed structure being located between the line terminal (2) and the fixing plate (71); The shed structure comprises two first vertical plates (62) located on the second surface (12) and perpendicular to the second surface (12) and distributed on both sides of the conductive bar (3); or The secondary wiring terminal (72) is located on the second surface (12), and the shed structure comprises two second vertical plates (64) and a plurality of second horizontal plates (63), wherein the two second vertical plates (64) are perpendicular to the first surface (11) and distributed on both sides of the line terminal (2), and the second horizontal plates (63) are located between the secondary wiring terminal (72) and the conductive bar (3). The length of the first horizontal plate (61) protruding from the first surface (11) is greater than the length of the line terminal (2) protruding from the first surface (11), or the length of the first horizontal plate (61) protruding from the first surface (11) is equal to the length of the line terminal (2) protruding from the first surface (11).

6. The current transformer of claim 5, wherein, The line terminal (2) is a copper bar, the static contact (81) comprises a tubular body and a flat end connected to the tubular body, and the line terminal (2) is used for connecting the flat end.

7. The current transformer of claim 1, wherein, ​ 8. The current transformer of claim 1, wherein, The housing (1) is cuboid, and at least one set of two adjacent surfaces of the housing (1) has a transition (14) therebetween.

9. The current transformer of any of claims 1-8, wherein, The first surface (11) is perpendicular to the second surface (12).

10. Switchgear, characterized in that A circuit breaker comprising a current transformer according to any one of claims 1-9.

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