Current transformer for switchgear and switchgear

Abstract

This utility model provides a current transformer and a switch cabinet for use in switchgear. The current transformer includes: a housing having a first surface and a second surface adjacent to each other; an internal conductor located inside the housing; an incoming terminal connected to the internal conductor and located on the first surface, the incoming terminal being used to connect to the stationary contact of a circuit breaker; a first umbel structure located on the first surface and surrounding the incoming terminal, the first umbel structure including several semi-annular ribs; and an outgoing terminal connected to the internal conductor and extending from the second surface.

Description

Technical Field

[0001] This utility model relates to the field of switchgear, and in particular to a current transformer and switchgear for use in switchgear cabinets. 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 for switchgear, 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 input terminal, which is connected to the internal conductor and located on the first surface, is used to connect to the stationary contact of the circuit breaker;

[0009] A first umbrella skirt structure is located on the first surface and surrounds the incoming terminal. The first umbrella skirt structure includes several semi-annular ribs.

[0010] Outgoing terminal, which is connected to the internal conductor and extends from the second surface.

[0011] In this way, by setting the incoming and outgoing terminals of the current transformer on two adjacent surfaces, the incoming terminals can be directly connected to the stationary contact, thereby reducing the overlapping surface caused by the use of the lower branch and ensuring phase-to-phase insulation.

[0012] Optionally, several of the semi-annular ribs can be concentric, as described above, in the current transformer. This facilitates the calculation of creepage distance and its effectiveness.

[0013] According to the current transformer described above, optionally, the ends of several of the semi-annular ribs on the same side are stepped. This increases the creepage distance.

[0014] Optionally, the outgoing terminals of the current transformer described above are perpendicular to the first surface. This arrangement is versatile, for example, suitable for narrow cabinets, and facilitates connection to lower branch lines.

[0015] According to the current transformer described above, optionally, at least a portion of the internal conductor is integrally formed with the incoming terminal; and / or

[0016] The stationary contact is a tubular body.

[0017] Optionally, the current transformer described above may further include a secondary terminal block located on a third surface of the housing, the third surface being disposed opposite to the first surface; and / or

[0018] A second umbrella-shaped structure is located on the third surface, the second umbrella-shaped structure comprising a plurality of horizontal plates parallel to the second surface.

[0019] This utility model also provides a switch cabinet, including the current transformer as described in any of the preceding claims.

[0020] Optionally, the switch cabinet described above may also include:

[0021] The U-shaped insulating cover includes two detachable bent plates whose bent portions can overlap to form the base plate of the U-shaped insulating cover. The base plate of the U-shaped insulating cover is used to fix it to the second surface, and the outgoing terminal is located in the U-shaped insulating cover. The use of two detachable bent plates facilitates installation.

[0022] Optionally, according to the switchgear described above, the outgoing terminal is used to connect to the stationary contact of the grounding switch via the lower branch line, and the U-shaped insulating cover is provided over the lower branch line and the stationary contact.

[0023] Optionally, according to the switchgear described above, the switchgear has three phases, each phase corresponding to one current transformer, and the three current transformers are arranged in a linear pattern. Two U-shaped insulating covers are used, one on each side of the current transformer. This allows for isolation between the three current transformers using fewer U-shaped insulating covers, thus reducing costs. Attached Figure Description

[0024] 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:

[0025] Figure 1 This is a partial structural diagram of the cable compartment of the switchgear according to the present invention.

[0026] Figure 2 This is a schematic diagram of the connection between a current transformer and a grounding switch according to an embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of the structure of a current transformer according to an embodiment of the present invention from one angle.

[0028] Figure 4 According to Figure 3 A schematic diagram of the current transformer from another angle.

[0029] Figure 5 This is a schematic diagram of the U-shaped insulating cover.

[0030] The accompanying figure is labeled as follows:

[0031] 1-Shell

[0032] 11-First Surface

[0033] 12-Second Surface

[0034] 13-Top surface

[0035] 131-Screw Hole

[0036] 132-bolt

[0037] 14-Transition Section

[0038] 15-Third Surface

[0039] 2-Incoming terminal

[0040] 3-First umbrella skirt structure

[0041] 31- Semi-circular ribs

[0042] 32-dashed line

[0043] 4-Outgoing terminal

[0044] 5-Secondary wiring terminals

[0045] 6-Second umbrella skirt structure

[0046] 61-Horizontal Plate

[0047] 7-U-shaped insulating cover

[0048] 71-Bending plate

[0049] 72-Bending section

[0050] 73-Through Hole

[0051] 81-Stationary Contact

[0052] 91-Static Touch Knife

[0053] 92-Support Insulator

[0054] 93-Framework

[0055] 94-Lower Branch Row

[0056] 95-Moving Tentacle Detailed Implementation

[0057] 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.

[0058] This utility model provides a current transformer that can be directly connected to the stationary contact 81, reducing the contact area. Generally, a circuit breaker has three phases, each phase having one stationary contact 81 and one moving contact (not shown in the figure), and correspondingly, each phase has one current transformer. Typically, the stationary contacts 81 of the circuit breaker are arranged side-by-side, such as... Figure 1 As shown, current transformers are also arranged side by side, and each current transformer must be phase-to-phase insulated from the next.

[0059] like Figures 1 to 5 As shown, the current transformer includes a housing 1, an internal conductor, an incoming terminal 2, a first shed structure 3, and an outgoing terminal 4.

[0060] 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 inlet terminal 2 and the outlet terminal 4 disposed 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 13, and one bottom surface. For easy demolding, the housing 1 has at least one set of transition portions 14 between adjacent surfaces. Figures 1 to 4 As shown, there is a transition section 14 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 13. There is no transition section 14 between the two sides with smaller surface areas and the bottom or top surface 13. Because of their smaller surface areas, they experience less resistance during demolding, so the transition section 14 can be omitted. Furthermore, the presence of this transition section 14 ensures that the locations where two adjacent current transformers are prone to discharge are as far apart as possible, thereby minimizing the creepage effect between them.

[0061] 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 outgoing terminal 4 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.

[0062] The input terminal 2 is connected to the internal conductor and located on the first surface 11. Specifically, the input terminal 2 can be exposed from the first surface 11, and the input terminal 2 is used to connect to the stationary contact 81 of the circuit breaker. The stationary contact 81 is located on the same phase as the current transformer. As an example, most of the input terminal 2 is located in the housing 1, with a small portion exposed from the first surface 11 for connecting to the stationary contact 81. This exposure 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 the input terminal 2 protrudes only slightly from the first surface 11, allowing for better connection to the stationary contact 81. As another example, the length of the input terminal 2 protruding from the first surface 11 can be selected according to actual needs, for example, in a cylindrical shape. As yet another example, the input terminal 2 may not protrude from the first surface 11 at all. 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, the input terminal 2 can also be integrally formed with the stationary contact 81, which not only simplifies the process but also reduces heat generation.

[0063] More specifically, a portion of the internal conductor, the incoming 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 incoming 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 2The diagram shows the case where the input terminal 2 and the stationary contact 81 are integrally formed. The portion connecting the input terminal 2 to the internal conductor is not shown in the diagram. The input terminal 2 and the internal conductor can also be integrally formed. The input terminal 2 has a threaded hole (not shown in the diagram). If the input terminal 2 is tubular, its end is closed and has a threaded hole. If the input terminal 2 is a conductive rod, a threaded 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 threaded hole. In the case of the tubular stationary contact 81, its end also has a hole. A bolt (not shown in the diagram) can pass through the hole from inside the stationary contact 81 to be screwed into the threaded hole of the input terminal 2. This connection method is simple and quick, and ensures that there is no direct threaded connection on the primary side, avoiding welding. Of course, part of the internal conductor can also be cylindrical, the input terminal 2 is a copper busbar, and the stationary contact 81 includes a tubular body and a flat end connected to the tubular body (not shown in the diagram). The input terminal 2 is used to connect to the flat end. As another example, if the current is small and welding will not occur, the incoming terminal 2 and the stationary contact 81 can be directly connected by threads, so that the stationary contact 81 can be removed from the incoming terminal 2 later.

[0064] The stationary contact 81 here can be tubular, specifically 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 to improve heat dissipation efficiency.

[0065] The first umbrella-shaped structure 3 is located on the first surface 11 and surrounds the incoming terminal 2. The first umbrella-shaped structure 3 includes several semi-annular ribs 31. The number of semi-annular ribs 31 can be set according to actual needs. Figure 3 and Figure 4 Three semi-circular ribs 31 are shown. From Figure 4 As can be seen, the top surface 13 has several screw holes 131. These screw holes 131 are at a low potential, and electric arcs will creep towards these screw holes 131. Therefore, a skirt structure is needed to increase the creepage distance. The length of the first skirt structure 3 protruding from the first surface 11 can be greater than the length of the input terminal 2 protruding from the first surface 11. In this way, the creepage distance between the stationary contact 81 and the top surface 13 of the current transformer can be maximized. Alternatively, the length of the semi-annular rib 31 in the first skirt structure 3 protruding from the first surface 11 can be equal to the length of the input terminal 2 protruding from the first surface 11. This can prevent the first skirt structure 3 from affecting the heat dissipation of the stationary contact 81. The first skirt structure 3 uses several semi-annular ribs 31, which can both increase the creepage distance and make the air inlet below large enough to help heat dissipation. Here, the semi-annular rib 31 can be understood as part of a ring, not necessarily half of a ring. The ring can specifically be racetrack-shaped, and the semi-annular represents part of the racetrack.

[0066] As an example, several semi-circular ribs 31 are concentric, which facilitates the calculation of creepage distance and effect.

[0067] As another example, the ends of several semi-annular ribs 31 on the same side ( Figure 3 The dashed line 32 connecting the ends of the semi-annular ribs 31 on the same side is shown in a stepped shape, which increases the creepage distance. Figure 3 and Figure 4 As shown, after the electric arc passes through the innermost semi-circular rib 31, it will reach the adjacent semi-circular rib 31. Compared with setting the ends of several semi-circular ribs 31 on the same side to be flush, it has a longer creepage distance.

[0068] Outgoing terminal 4 is connected to the internal conductor and extends from the second surface 12. Specifically, outgoing terminal 4 may be a copper busbar. Outgoing terminal 4 is used as an outgoing terminal 4. Outgoing terminal 4 is used to connect to external equipment, such as a grounding switch via the lower branch busbar 94. Figure 1 and Figure 2 As shown, the lower branch 94 is also a copper busbar, or the outgoing terminal 4 is connected to a copper busbar in the cable or switch cabinet housing. Figures 1 to 4 As shown, the outgoing terminal 4 is perpendicular to the first surface 11. This configuration is highly adaptable, for example, it is suitable for narrow cabinets and facilitates connection to the lower branch row 94.

[0069] 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.

[0070] In this way, by setting the incoming terminal 2 and the outgoing terminal 4 of the current transformer on two adjacent surfaces, the incoming terminal 2 can be directly connected to the stationary contact 81, thereby reducing the overlapping surface caused by the use of the lower branch 94 and ensuring phase-to-phase insulation.

[0071] As another example, the current transformer also includes a secondary terminal block 5, the position of which on the housing 1 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 5 is located on the third surface 15 of the housing 1, which is opposite to the first surface 11. The secondary terminal 5 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 2 and the output terminal 4.

[0072] As another example, the current transformer also includes a second shed structure 6. This second shed structure 6 is located on the third surface 15 and includes several horizontal plates 61 parallel to the second surface 12. This second shed structure 6 increases the creepage distance to ground and to the secondary wiring locations. The number of horizontal plates 61 can be set according to actual needs.

[0073] 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 on the top surface 13 of the cable compartment. Figure 1 , Figure 2 and Figure 4 As shown, the top surface 13 of the current transformer is provided with several screw holes 131, and the current transformer can be fixed to the top surface 13 of the cable compartment by bolts 132.

[0074] As an example, to improve phase-to-phase insulation, insulating components can be installed on both sides of the lower branch 94. For example... Figure 1 , Figure 2 and Figure 5 As shown, a U-shaped insulating cover 7 is installed on the current transformer. This U-shaped insulating cover 7 includes two detachable bent plates 71. The bent portions of the two plates 71 can overlap to form the base plate of the U-shaped insulating cover 7. The base plate of the U-shaped insulating cover 7 is used to fix it to the second surface 12, and the outgoing terminal 4 is located within the U-shaped insulating cover 7. The use of two detachable bent plates 71 facilitates installation; specifically, fasteners can be inserted through the bent portions 72 of the two plates 71 and fixed to the second surface 12. Figure 1 and Figure 2 As shown, the base plate of the U-shaped insulating cover 7 is fixed to the second surface 12. Specifically, the U-shaped insulating cover 7 can be fixed to the second surface 12 through fixing holes on the second surface 12, with fasteners passing through the fixing holes and through holes 73 on the base plate of the U-shaped insulating cover 7. The shape of the bent plate 72 of the U-shaped insulating cover 7 can be designed to avoid interference with other components in the switch cabinet, such as... Figure 5 As shown.

[0075] As another example, the outgoing terminal 4 is used to connect to the stationary contact 91 of the grounding switch via the lower branch 94, and a U-shaped insulating cover 7 is provided over the lower branch 94 and the stationary contact 91. The U-shaped insulating cover 7 can be long enough in the direction perpendicular to the second surface 12 to cover the lower branch 94 and the stationary contact 91, so that the lower branch 94 and the stationary contact 91 between adjacent phases can also achieve good insulation.

[0076] More specifically, such as Figure 1As shown, the switchgear has three phases, each corresponding to one current transformer. The three current transformers are arranged in a linear configuration, and there are two U-shaped insulating covers 7, one on each side of the current transformer. This allows for isolation between the three current transformers using fewer U-shaped insulating covers 7, thus reducing costs. Figure 1 As shown, the flat plate portion of the bent plate 71 is located between the two current transformers, which means that the two current transformers share the flat plate portion of the bent plate 71.

[0077] like Figure 1 and Figure 2 As shown, the switchgear also includes a grounding switch. The outgoing terminal 4 is connected to the grounding switch via a lower branch 94, specifically to the stationary contact 91 of the grounding switch. The stationary contact 91 of the grounding switch is fixed to a supporting insulator 92, which is fixed to a frame 93. The lower branch 94 here is, for example, a copper busbar. The grounding switch also has a moving contact 95, which can be rotated to contact or separate from the stationary contact 91.

[0078] 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 for use in switchgear, characterized in that, include: A housing (1) having a first surface (11) and a second surface (12) adjacent to each other; An internal conductor located within the housing (1); The incoming terminal (2) is connected to the internal conductor and located on the first surface (11), and the incoming terminal (2) is used to connect to the stationary contact (81) of the circuit breaker. A first umbrella skirt structure (3) is located on the first surface (11) and surrounds the incoming terminal (2). The first umbrella skirt structure (3) includes several semi-annular ribs (31). Outgoing terminal (4), which is connected to the internal conductor and extends from the second surface (12).

2. The current transformer according to claim 1, characterized in that, Several of the aforementioned semi-circular ribs (31) are concentric.

3. The current transformer according to claim 1, characterized in that, The ends of several of the semi-annular ribs (31) on the same side are stepped.

4. The current transformer according to claim 1, characterized in that, The outgoing terminal (4) is perpendicular to the first surface (11).

5. The current transformer according to claim 1, characterized in that, At least a portion of the internal conductor is integrally formed with the incoming terminal (2); and / or The stationary contact (81) is a tubular body.

6. The current transformer according to any one of claims 1-5, characterized in that, It also includes a secondary terminal block (5), which is located on the third surface (15) of the housing (1), the third surface (15) being disposed opposite to the first surface (11); and / or A second umbrella skirt structure (6) is located on the third surface (15). The second umbrella skirt structure includes several horizontal plates (61) and the horizontal plates (61) are parallel to the second surface (12).

7. A switch cabinet, characterized in that, Includes the current transformer according to any one of claims 1-6.

8. The switch cabinet according to claim 7, characterized in that, Also includes: The U-shaped insulating cover (7) includes two detachable bending plates (71), the bent portions (72) of which can overlap to form the base plate of the U-shaped insulating cover (7), the base plate of which is used to fix to the second surface (12) and the outgoing terminal (4) is located in the U-shaped insulating cover (7).

9. The switchgear according to claim 8, characterized in that, The outgoing terminal (4) is used to connect to the stationary contact (91) of the grounding switch via the lower branch (94), and the U-shaped insulating cover (7) is provided on the lower branch (94) and the stationary contact (91).

10. The switchgear according to claim 8, characterized in that, The switch cabinet has three phases, each phase is corresponding to a current transformer, the three current transformers are arranged in a linear manner, and there are two U-shaped insulating covers (7), which are respectively set on the current transformers on both sides.

Images