Current transformer and switch cabinet
By placing the incoming and outgoing terminals on two adjacent surfaces in the current transformer to directly connect the stationary contact, and using an umbrella skirt structure to enhance insulation, the phase-to-phase insulation problem when the CT is connected to the stationary contact of the circuit breaker in the switch cabinet is solved, achieving higher safety and simplified assembly.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2026-03-13
AI Technical Summary
In the prior art, when the current transformer (CT) of the switchgear is connected to the stationary contact of the circuit breaker, there is a phase-to-phase insulation problem caused by the connection of the stationary contact to the branch line.
Design a current transformer that places the input and output terminals on two adjacent surfaces, allowing them to be directly connected to the stationary contact, reducing the overlap area, and increasing the creepage distance and insulation protection through the umbrella skirt structure.
It effectively reduces phase-to-phase insulation problems, simplifies assembly procedures, and improves the reliability and safety of the connection between current transformers and circuit breakers.
Smart Images
Figure CN223993203U_ABST
Abstract
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] Outgoing terminals are connected to the internal conductor and extend from the second surface.
[0010] By placing the output and input terminals of the current transformer on two adjacent surfaces, the input terminal can be directly connected to the stationary contact, thereby reducing the overlap caused by the use of branch conductors and ensuring phase-to-phase insulation.
[0011] Optionally, the outgoing terminal is a conductor bar, as described above, based on the current transformer described above; and / or
[0012] The first surface is perpendicular to the second surface.
[0013] According to the current transformer described above, optionally, the side of the conductive bus faces the first surface. This maximizes the spacing between the two outgoing terminals to meet the phase-to-phase insulation requirements.
[0014] According to the current transformer described above, optionally, at least a portion of the internal conductor is integrally formed with the incoming terminal. This reduces assembly steps and simplifies the process.
[0015] According to the current transformer described above, optionally, the input terminal is a conductive rod or conductive tube with a screw hole, and the stationary contact is screwed to the input terminal, wherein the stationary contact is a conductive rod or conductive tube; or
[0016] The incoming terminal and the stationary contact are integrally formed.
[0017] Optionally, the housing is used to fix the current transformer as described above to the mounting plate.
[0018] The current transformer further includes a first skirt disposed on the first surface and located between the outgoing terminal and the fixing plate, or the current transformer further includes a second skirt disposed on the first surface and surrounding the outgoing terminal. The skirt structure can increase the creepage distance.
[0019] Optionally, the current transformer described above may also include at least one of the following structures:
[0020] A secondary wiring terminal is located on the third surface of the housing, which is disposed opposite to the first surface;
[0021] The mounting hole is located on the fourth surface of the housing, which is opposite to the second surface. The current transformer can be fixed to the top of the cable compartment of the switchgear through the mounting hole.
[0022] Optionally, the housing of the current transformer described above is a cube, with a transition between at least one set of adjacent surfaces. This maximizes the distance between the points where two adjacent current transformers are likely to discharge, thereby minimizing creepage interference between them.
[0023] This utility model also provides a switch cabinet, including the current transformer and circuit breaker described in any of the above claims, wherein the current transformer is located at the top of the cable compartment of the switch cabinet. This allows it to be as close as possible to the stationary contacts of the circuit breaker, facilitating assembly.
[0024] Optionally, the switchgear described above may further include a grounding switch, wherein the outgoing terminals are connected to the grounding switch via conductive elements. Attached Figure Description
[0025] 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:
[0026] Figure 1 This is a schematic diagram of the structure of a current transformer according to an embodiment of the present invention.
[0027] Figure 2 According to Figure 1 A schematic diagram of the current transformer from another angle.
[0028] Figure 3 This is a schematic diagram of the structure of a current transformer according to another embodiment of the present invention.
[0029] Figure 4 This is a partial structural diagram of the cable compartment of the switchgear according to the present invention.
[0030] The reference numerals in the attached figures are as follows:
[0031] 11-Shell
[0032] 111-First Surface
[0033] 112-Second Surface
[0034] 1121-Fixing Hole
[0035] 113-Third Surface
[0036] 114 - Fourth Surface
[0037] 115-Transition Section
[0038] 13-Incoming Terminal
[0039] 14-Outgoing terminal
[0040] 151 - First Umbrella Skirt
[0041] 152 - Second Umbrella Skirt
[0042] 16-Secondary wiring terminal
[0043] 17-Mounting Holes
[0044] 18-Insulating Cover
[0045] 21-Stationary contacts of circuit breakers
[0046] 31-Stationary contact of grounding switch
[0047] 32-Support Insulator
[0048] 33-Framework
[0049] 4-Conductive components
[0050] 5- The top plate of the cable compartment Detailed Implementation
[0051] 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.
[0052] 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; correspondingly, each phase has one current transformer. Typically, such as... Figure 4 As shown, the stationary contacts 21 of the circuit breaker are arranged side by side, and the current transformers are also arranged side by side. Each current transformer must meet the requirements of phase-to-phase insulation.
[0053] like Figures 1 to 4 As shown, the current transformer includes a housing 11, an internal conductor, an input terminal 13, and an output terminal 14.
[0054] The housing 11 has a first surface 111 and a second surface 112, which are adjacent to each other. For example, the first surface 111 and the second surface 112 are perpendicular to each other, so that the distance between the incoming terminal 13 and the outgoing terminal 14 disposed thereon can be maximized to avoid interference between them. The housing 11 can be an insulating material, such as epoxy resin. As an example, the housing 11 can be a cube with six surfaces: four side surfaces, one top surface, and one bottom surface. For easy demolding, the housing 11 has a transition portion 115 between at least one set of adjacent pairs of surfaces. Figures 1 to 3 As shown, there is a transition section 115 between any two adjacent sides of the four sides, as well as between the side and the bottom surface and between the side and the top surface. Of course, the transition section 115 can be omitted depending on the position of the internal components, and the specific selection can be made according to actual needs. In addition, the presence of this transition section 115 makes the positions where two adjacent current transformers are prone to discharge as far apart as possible, thereby minimizing the creepage effect between them.
[0055] An internal conductor (not shown in the figure) is located inside the housing 11 and is used to connect the incoming terminal 13 and the outgoing terminal 14 to form a circuit. This internal conductor may include multiple components to realize the function of the current transformer; the specific structure is prior art and will not be described in detail here.
[0056] The input terminal 13 is connected to the internal conductor and exposed from the first surface 111. The input terminal 13 is used to connect to the stationary contact 21 of the circuit breaker. This stationary contact 21 corresponds to the same phase as the current transformer. As an example, the input terminal 13 is mostly located within the housing 11, with a small portion exposed from the first surface 111 for connecting to the stationary contact 21. This exposure can be understood as the input terminal 13 being visible when facing the first surface 111. Figure 1 and Figure 3 The diagram shows the input terminal 13 with only a small portion protruding from the first surface 111. This allows for better connection to the stationary contact. Of course, the length of the input terminal 13 protruding from the first surface 111 can be selected according to actual needs. As an example, the input terminal 13 is integrally formed with at least a portion of the internal conductor. This integrally formed portion is, for example, a cylinder, which can be solid or hollow. This reduces assembly steps and simplifies the process. As another example, such as... Figures 1 to 4 As shown, the input terminal 13 is a conductive rod or conductive tube, specifically made of copper. A screw hole is provided at the end of the input terminal 13, and a stationary contact 21, also a conductive rod or conductive tube, is screwed onto the input terminal 13. Thus, the stationary contact 21 can be connected to the input terminal 13 through the screw hole. Furthermore, at least a portion of the internal conductor can also be a conductive rod or conductive tube, integrally formed with the input terminal 13. For example, the portion of the internal conductor connected to the input terminal 13, the input terminal 13, and the stationary contact 21 are all integrally formed as a conductive rod or conductive tube, simplifying the assembly process.
[0057] The outgoing terminal 14 is connected to the internal conductor and extends from the second surface 112. As an example, the outgoing terminal 14 is a conductive busbar, more specifically, a copper busbar. The outgoing terminal 14 is used to connect to external devices, such as a grounding switch via the conductive element 4. Figure 4 As shown, the conductive component 4 is also a conductive bus, or the output terminal 14 is connected to a cable. As an example, to improve phase-to-phase insulation, insulating covers 18 can be provided on both sides of the output terminal 14. Figures 1 to 3 As shown, the fixing hole 1121 on the second surface 112 can be used to install the insulating cover 18, which is U-shaped and covers the outgoing terminal 14, the conductive element 4 connected to the outgoing terminal 14, and the stationary contact 31 of the grounding switch. Of course, the insulating component can also be formed directly on the housing 11, for example, by forming two insulating plates on both sides of the second surface 112, and these two insulating plates are integrally formed with the housing 11. The insulating plates are relatively long and can cover the outgoing terminal 14, the connected conductive element 4, and the stationary contact 31 of the grounding switch, thus reducing the steps of installing the insulating cover 18 and simplifying the assembly process.
[0058] As an example, when the outgoing terminal 14 is a conductive bus, the side of the conductive bus faces the first surface 111, such as... Figures 1 to 4 As shown. This arrangement is equivalent to the outgoing terminal 14 being positioned opposite to the outgoing terminal 14 on the adjacent current transformer, maximizing the distance between them to meet the phase-to-phase insulation requirements. Furthermore, this arrangement facilitates the installation of the conductive element 4 between the conductor busbar and the stationary contact 21 of the circuit breaker.
[0059] The stationary contact 21 here can be a conductive rod or a conductive tube, and the material can be copper. The stationary contact 21 can be provided with parallel heat dissipation holes. Specific details are omitted. Furthermore, the end of the stationary contact 21 away from the housing 11 has rounded corners to reduce the possibility of tip discharge.
[0060] Furthermore, the circuit transformer may also include a secondary terminal block 16, the position of which on the housing 11 can be selected according to the location of the current transformer installed in the cable compartment. For example... Figures 1 to 4 As shown, the secondary terminal 16 is located on the third surface 113 of the housing 11, which is opposite to the first surface 111. The secondary terminal 16 is used to monitor the online current, and it can calculate the current of the primary circuit from the induced current in the circuit formed by the input terminal 13 and the output terminal 14.
[0061] As an example, the shell 11 can be completed using a one-piece casting process.
[0062] In this invention, by placing the output terminal 14 and the input terminal 13 of the current transformer on two adjacent surfaces, the input terminal 13 can be directly connected to the stationary contact 21, thereby reducing the overlap surface caused by the use of branch conductors and ensuring phase-to-phase insulation.
[0063] As an example, the housing 11 is used for fixing to the mounting plate. The current transformer also includes a skirt structure. For ease of description, Figure 1 and Figure 2 The umbrella-shaped structure shown is called the first umbrella-shaped structure 151. Figure 3 The umbrella-shaped structure shown is called the second umbrella skirt 152. The first umbrella skirt 151 is disposed on the first surface 111 and located between the outgoing terminal 14 and the fixing plate. The fixing plate can be a separate plate fixed to the current transformer, which can then be fixed to the switchgear. Alternatively, the fixing plate can be part of the switchgear frame, such as the side wall or top plate of the cable compartment. The first umbrella skirt 151 can be as follows... Figure 1 and Figure 2As shown, the first umbrella skirt is a horizontal stripe that increases the creepage distance to ground and secondary wiring positions. The length of the first umbrella skirt 151 protruding from the first surface 111 can be greater than the length of the incoming terminal 13 protruding from the first surface 111. This maximizes the creepage distance between the stationary contact 21 and the mounting plate to which the current transformer is fixed. Alternatively, the length of the first umbrella skirt 151 protruding from the first surface 111 can be equal to the length of the incoming terminal 13 protruding from the first surface 111, thus preventing the first umbrella skirt 151 from affecting the heat dissipation of the stationary contact 21. The second umbrella skirt 152 is disposed on the first surface 111 and surrounds the outgoing terminal 14. This structure of the second umbrella skirt 152 provides all-around insulation protection for the outgoing terminal 14.
[0064] As an example, the housing 11 can be directly fixed to the cable compartment. For instance, the fourth surface 114 of the housing 11 is provided with several mounting holes 17, which are opposite to the second surface 112. The current transformer can be fixed to the top of the cable compartment of the switchgear through the mounting holes 17, specifically to the top plate 5 of the cable compartment. This avoids the need for a separate fixing plate, which not only simplifies the assembly process but also contributes to the compactness and miniaturization of the overall switchgear structure.
[0065] 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, wherein the current transformer is located at the top of the cable compartment of the switch cabinet. Positioning the current transformer at the top of the cable compartment facilitates its fixation within the cable compartment and allows it to be as close as possible to the stationary contact 21 of the circuit breaker, thus facilitating assembly. Figure 4 Part of the structure inside the cable compartment is shown.
[0066] like Figure 4 As shown, the switch cabinet also includes a grounding switch. The outgoing terminal 14 is connected to the grounding switch via a conductive element 4, specifically to the stationary contact 31 of the grounding switch. The stationary contact 31 is fixed to a supporting insulator, which is fixed to the frame.
[0067] The above are merely preferred embodiments of the present utility model and are 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 shall be included within the protection scope of the present utility model.
Claims
1. A current transformer, characterized by Comprising: a housing (11) having a first surface (111) and a second surface (112) adjacent to each other; an internal conductor located in the housing (11); a line-in terminal (13) connected to the internal conductor and exposed from the first surface (111), the line-in terminal (13) being used for connecting to a static contact (21) of a circuit breaker; a line-out terminal (14) connected to the internal conductor and extending from the second surface (112).
2. The current transformer of claim 1, wherein, the line-out terminal (14) is a conductive bar; and / or the first surface (111) is perpendicular to the second surface (112).
3. The current transformer of claim 2, wherein, a side edge of the conductive bar faces the first surface (111).
4. The current transformer of claim 1, wherein, at least a part of the internal conductor is integrally formed with the line-in terminal (13).
5. The current transformer of claim 1, wherein, the line-in terminal (13) is a conductive rod or a conductive tube, which is provided with a threaded hole, the static contact (21) being screwed to the line-in terminal (13), the static contact (21) being a conductive rod or a conductive tube; or the line-in terminal (13) is integrally formed with the static contact (21).
6. The current transformer of claim 1, wherein, the housing (11) is used for being fixed on a fixed plate; the current transformer further comprises a first umbrella skirt (151) arranged on the first surface (111) and located between the line-out terminal (14) and the fixed plate, or the current transformer further comprises a second umbrella skirt (152) arranged on the first surface (111) and surrounding the line-out terminal (14).
7. The current transformer of claim 1, wherein, Further comprising at least one of the following structures: a secondary wiring terminal (16) located on a third surface (113) of the housing (11), the third surface (113) being oppositely arranged with the first surface (111); a mounting hole (17) located on a fourth surface (114) of the housing (11), the fourth surface (114) being opposite to the second surface (112), the current transformer being able to be fixed on a top of a cable compartment of a switch cabinet through the mounting hole (17).
8. The current transformer of any of claims 1-7, wherein, the housing (11) is a cube, and at least one set of two adjacent surfaces in the housing (11) has a transition (115) therebetween.
9. Switchgear cabinet, characterized in that comprising the current transformer according to any one of claims 1-8 and a circuit breaker, the current transformer being located on a top of a cable compartment of a switch cabinet.
10. Switchgear according to claim 9, characterized in that Further comprising: a grounding switch, the line-out terminal (14) being connected to the grounding switch through a conductive piece (4).