A transformer core, a transformer coil and a current transformer

Abstract

The application provides a mutual inductor core, a mutual inductor coil and a current transformer. The mutual inductor core comprises a protective shell, a core body arranged in the protective shell and a cover plate cooperating with the protective shell to form a sealed cavity. The mutual inductor core further comprises a compensation reactor arranged in the protective shell. The protective shell or the cover plate is provided with a wire outlet hole through which the lead-out wire of the compensation reactor passes. The compensation reactor (i.e. a compensation small coil) is built in the protective shell, i.e. the mutual inductor core directly integrates the compensation reactor. The protective shell or the cover plate is provided with the wire outlet hole through which the lead-out wire of the compensation reactor passes. Thus, the compensation reactor can be directly connected with the electromagnetic wire wound outside the mutual inductor core, i.e. the two are connected in advance. Thus, only the connection of the mutual inductor coil is needed in the control and distribution cabinet, the connection is convenient, and the compensation reactor no longer occupies the space in the control and distribution cabinet.

Description

Technical Field

[0001] This invention relates to the field of current transformer technology, specifically to a current transformer core, a current transformer coil, and a current transformer. Background Technology

[0002] A current transformer coil generally consists of a transformer core and electromagnetic wire wound around the outside of the core. The transformer core includes a casing, a core body housed within the casing, and a cover plate that cooperates with the casing to form a sealed cavity. Ultra-high voltage current transformer coils used in 500kV and above voltage level lines generally consist of measuring, metering, protection, and TPY transient protection coils. The metering and measuring coils typically have instrument safety factor requirements. For most parameters, the coil design requires the addition of a compensating reactor (i.e., a compensating small coil) to compensate for instrument safety factors or errors, thereby meeting the coil's electrical performance requirements.

[0003] like Figure 1 As shown, the compensating reactor is generally an external structure, placed in the control cabinet 100, while the current transformer 200 is located between the GIS circuit breaker 300 and the disconnecting switch 400. The installation position of the current transformer 200 is a certain distance from the control cabinet 100. After the current transformer coil output line is connected to the control cabinet 100, the compensating reactor also needs to be connected to the current transformer coil. The wiring is inconvenient and the operation is relatively troublesome. In addition, the compensating reactor also occupies space inside the control cabinet 100. Summary of the Invention

[0004] The purpose of this invention is to provide a current transformer core to solve the problem of inconvenient wiring and space occupation caused by the external placement of the compensation reactor of the current transformer coil in the control cabinet; the purpose of this invention is also to provide a current transformer coil to solve the problem of inconvenient wiring and space occupation caused by the external placement of the compensation reactor of the current transformer coil in the control cabinet; the purpose of this invention is also to provide a current transformer to solve the problem of inconvenient wiring and space occupation caused by the external placement of the compensation reactor of the current transformer coil in the control cabinet.

[0005] To achieve the above objectives, the current transformer core in this invention adopts the following technical solution: A current transformer core includes a housing, a core disposed within the housing, and a cover plate that cooperates with the housing to form a sealed cavity. The current transformer core also includes a compensating reactor disposed within the housing. The housing or cover plate is provided with an outlet hole for the lead wire of the compensating reactor to pass through.

[0006] The beneficial effects of the above technical solution are as follows: the compensating reactor (i.e., the compensating small coil) is built into the housing, that is, the compensating reactor is directly integrated into the transformer core. The housing or cover plate is provided with a lead hole for the lead wire of the compensating reactor to pass through. In this way, the compensating reactor can be directly connected to the electromagnetic wire wound on the outside of the transformer core. That is, the two can be connected in advance. In this way, only the wiring of the transformer coil needs to be done in the control cabinet. The wiring is more convenient, and the compensating reactor no longer occupies space in the control cabinet.

[0007] Furthermore, both the protective shell and the cover plate are circular, with the cover plate being formed by splicing together at least two arc-shaped plates.

[0008] The advantages of the above technical solution are: it facilitates processing and manufacturing, improves the utilization rate of the board material, and facilitates the installation of the compensation reactor.

[0009] Furthermore, the outlet hole is located on the arc-shaped plate corresponding to the compensating reactor.

[0010] The advantages of the above technical solution are: it facilitates the installation and outgoing lines of the compensation reactor.

[0011] Furthermore, one of the two adjacent curved plates is provided with a protrusion, and the other curved plate is provided with a groove that matches the shape of the protrusion so that the protrusion can be inserted.

[0012] The beneficial effects of the above technical solution are: to avoid displacement between two adjacent curved plates and to ensure the strength of the connection.

[0013] Furthermore, both the protrusions and the grooves are semi-circular.

[0014] The advantages of the above technical solution are: it facilitates processing and docking.

[0015] Furthermore, the casing includes a base plate and an inner wall and an outer wall connected to the base plate. The casing also includes a reinforcing wall connected to the base plate and located between the inner wall and the outer wall. The core is disposed between the inner wall and the reinforcing wall, and the compensating reactor is disposed between the reinforcing wall and the outer wall.

[0016] The beneficial effects of the above technical solution are: it increases the compressive strength of the casing and facilitates the arrangement of the core and the compensating reactor.

[0017] Furthermore, a reinforcing rib is provided between the base plate and the reinforcing wall. The reinforcing rib is triangular, with one right-angled side connected to the base plate and the other right-angled side connected to the reinforcing wall.

[0018] The beneficial effect of the above technical solution is that it further strengthens the structural strength of the protective shell.

[0019] Furthermore, the distance between the reinforcing wall and the outer wall is greater than the distance between the inner wall and the reinforcing wall.

[0020] The beneficial effects of the above technical solution are: it facilitates the arrangement of the core and the compensating reactor, and prevents the core from shifting.

[0021] To achieve the above objectives, the current transformer coil in this invention adopts the following technical solution: A current transformer coil includes a current transformer core and an electromagnetic wire wound around the outside of the current transformer core. The current transformer core includes a protective shell, a core body disposed within the protective shell, and a cover plate that cooperates with the protective shell to form a sealed cavity. The current transformer core also includes a compensating reactor disposed within the protective shell. The protective shell or the cover plate is provided with an outlet hole for the lead wire of the compensating reactor to pass through.

[0022] The beneficial effects of the above technical solution are as follows: the compensating reactor (i.e., the compensating small coil) is built into the housing, that is, the compensating reactor is directly integrated into the transformer core. The housing or cover plate is provided with a lead hole for the lead wire of the compensating reactor to pass through. In this way, the compensating reactor can be directly connected to the electromagnetic wire wound on the outside of the transformer core. That is, the two can be connected in advance. In this way, only the wiring of the transformer coil needs to be done in the control cabinet. The wiring is more convenient, and the compensating reactor no longer occupies space in the control cabinet.

[0023] Furthermore, both the protective shell and the cover plate are circular, with the cover plate being formed by splicing together at least two arc-shaped plates.

[0024] The advantages of the above technical solution are: it facilitates processing and manufacturing, improves the utilization rate of the board material, and facilitates the installation of the compensation reactor.

[0025] Furthermore, the outlet hole is located on the arc-shaped plate corresponding to the compensating reactor.

[0026] The advantages of the above technical solution are: it facilitates the installation and outgoing lines of the compensation reactor.

[0027] Furthermore, one of the two adjacent curved plates is provided with a protrusion, and the other curved plate is provided with a groove that matches the shape of the protrusion so that the protrusion can be inserted.

[0028] The beneficial effects of the above technical solution are: to avoid displacement between two adjacent curved plates and to ensure the strength of the connection.

[0029] Furthermore, both the protrusions and the grooves are semi-circular.

[0030] The advantages of the above technical solution are: it facilitates processing and docking.

[0031] Furthermore, the casing includes a base plate and an inner wall and an outer wall connected to the base plate. The casing also includes a reinforcing wall connected to the base plate and located between the inner wall and the outer wall. The core is disposed between the inner wall and the reinforcing wall, and the compensating reactor is disposed between the reinforcing wall and the outer wall.

[0032] The beneficial effects of the above technical solution are: it increases the compressive strength of the casing and facilitates the arrangement of the core and the compensating reactor.

[0033] Furthermore, a reinforcing rib is provided between the base plate and the reinforcing wall. The reinforcing rib is triangular, with one right-angled side connected to the base plate and the other right-angled side connected to the reinforcing wall.

[0034] The beneficial effect of the above technical solution is that it further strengthens the structural strength of the protective shell.

[0035] Furthermore, the distance between the reinforcing wall and the outer wall is greater than the distance between the inner wall and the reinforcing wall.

[0036] The beneficial effects of the above technical solution are: it facilitates the arrangement of the core and the compensating reactor, and prevents the core from shifting.

[0037] To achieve the above objectives, the current transformer in this invention adopts the following technical solution: A current transformer includes a current transformer housing and a current transformer coil disposed within the current transformer housing. The current transformer coil includes a current transformer core and an electromagnetic wire wound around the outside of the current transformer core. The current transformer core includes a protective shell, a core body disposed within the protective shell, and a cover plate that cooperates with the protective shell to form a sealed cavity. The current transformer core also includes a compensating reactor disposed within the protective shell. The protective shell or the cover plate is provided with an outlet hole for the lead wire of the compensating reactor to pass through.

[0038] The beneficial effects of the above technical solution are as follows: the compensating reactor (i.e., the compensating small coil) is built into the housing, that is, the compensating reactor is directly integrated into the transformer core. The housing or cover plate is provided with a lead hole for the lead wire of the compensating reactor to pass through. In this way, the compensating reactor can be directly connected to the electromagnetic wire wound on the outside of the transformer core. That is, the two can be connected in advance. In this way, only the wiring of the transformer coil needs to be done in the control cabinet. The wiring is more convenient, and the compensating reactor no longer occupies space in the control cabinet.

[0039] Furthermore, both the protective shell and the cover plate are circular, with the cover plate being formed by splicing together at least two arc-shaped plates.

[0040] The advantages of the above technical solution are: it facilitates processing and manufacturing, improves the utilization rate of the board material, and facilitates the installation of the compensation reactor.

[0041] Furthermore, the outlet hole is located on the arc-shaped plate corresponding to the compensating reactor.

[0042] The advantages of the above technical solution are: it facilitates the installation and outgoing lines of the compensation reactor.

[0043] Furthermore, one of the two adjacent curved plates is provided with a protrusion, and the other curved plate is provided with a groove that matches the shape of the protrusion so that the protrusion can be inserted.

[0044] The beneficial effects of the above technical solution are: to avoid displacement between two adjacent curved plates and to ensure the strength of the connection.

[0045] Furthermore, both the protrusions and the grooves are semi-circular.

[0046] The advantages of the above technical solution are: it facilitates processing and docking.

[0047] Furthermore, the casing includes a base plate and an inner wall and an outer wall connected to the base plate. The casing also includes a reinforcing wall connected to the base plate and located between the inner wall and the outer wall. The core is disposed between the inner wall and the reinforcing wall, and the compensating reactor is disposed between the reinforcing wall and the outer wall.

[0048] The beneficial effects of the above technical solution are: it increases the compressive strength of the casing and facilitates the arrangement of the core and the compensating reactor.

[0049] Furthermore, a reinforcing rib is provided between the base plate and the reinforcing wall. The reinforcing rib is triangular, with one right-angled side connected to the base plate and the other right-angled side connected to the reinforcing wall.

[0050] The beneficial effect of the above technical solution is that it further strengthens the structural strength of the protective shell.

[0051] Furthermore, the distance between the reinforcing wall and the outer wall is greater than the distance between the inner wall and the reinforcing wall.

[0052] The beneficial effects of the above technical solution are: it facilitates the arrangement of the core and the compensating reactor, and prevents the core from shifting. Attached Figure Description

[0053] Figure 1 This is a diagram illustrating the application of current transformers in existing technologies. Figure 1 In China: 100, control cabinet; 200, current transformer; 300, GIS circuit breaker; 400, disconnecting switch; Figure 2 This is a structural diagram of the transformer core in this invention; Figure 3 This is a structural diagram of the casing of the transformer core in this invention (without the compensating reactor). Figure 4 This is a structural diagram of an arc-shaped plate of the transformer core in this invention; Figure 5 This is a structural diagram of another arc-shaped plate of the current transformer core in this invention; Figure 6 This is a structural diagram of the casing of the current transformer core and the compensating reactor in this invention; Figure 7 This is a cross-sectional view of the transformer core in this invention; Figure 8 This is a schematic diagram of the structure of the transformer coil in this invention.

[0054] Figures 2-8 In the middle: 1. Sheath; 11. Base plate; 12. Inner wall; 13. Outer wall; 14. Reinforcing wall; 15. Amorphous ribbon filling area; 16. Reinforcing rib; 2. Arc plate; 21. Outlet hole; 22. Groove; 23. Protrusion; 3. Compensating reactor; 31. First end lead wire; 32. Tail end lead wire; 4. Amorphous ribbon; 5. Electromagnetic wire; 51. First end lead wire of coil; 52. Tail end lead wire of coil. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0056] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0057] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0059] Example 1 of the current transformer core in this invention is as follows: Figure 2 As shown, the device includes a protective shell 1 and a cover plate that cooperates with the protective shell 1 to form a sealed cavity. Both the protective shell 1 and the cover plate are annular. The inner and outer diameters of the cover plate match the inner and outer diameters of the protective shell 1. The cover plate is made of insulating material and is formed by splicing four equally sized arc-shaped plates 2. This facilitates processing and manufacturing, and improves the utilization rate of the material. Figure 4 and Figure 5 As shown, one of the two adjacent curved plates 2 has a protrusion 23, and the other curved plate 2 has a groove 22 that matches the shape of the protrusion 23 so that the protrusion 23 can be inserted. This can prevent the two adjacent curved plates from shifting and ensure the joint strength. That is, one end of the curved plate 2 has a protrusion 23 and the other end has a groove 22. Both the protrusion 23 and the groove 22 are semi-circular, which facilitates processing and jointing.

[0060] like Figure 3 , Figure 6 , Figure 7 As shown, the housing 1 is made of stainless steel and includes a base plate 11 and an inner wall 12 and an outer wall 13 connected to the base plate 11. The housing 1 also includes a reinforcing wall 14 connected to the base plate 11 and located between the inner wall 12 and the outer wall 13. The distance between the reinforcing wall 14 and the outer wall 13 is greater than the distance between the inner wall 12 and the reinforcing wall 14. The transformer core also includes a core body disposed between the inner wall 12 and the reinforcing wall 14, specifically an amorphous ribbon 4. Therefore, the base plate 11, the inner wall 12, and the reinforcing wall 14 form an amorphous ribbon filling region 15.

[0061] The outer diameter of the coil used in ultra-high voltage current transformers is generally above 800mm, and the primary current is above 2500A. During coil design, a structure with a large core size and insufficient amorphous strip filling may occur. Therefore, placing the amorphous strip 4 within a relatively narrow amorphous strip filling area 15 can prevent the amorphous strip 4 from shifting. Furthermore, during coil assembly, the coil is affected by assembly pressure. If the sheath strength is insufficient, the amorphous strip will deform under pressure, resulting in unqualified excitation data and ultimately unqualified coil error. The reinforcing wall 14 can improve the compressive strength of the sheath 1. Furthermore, eight reinforcing ribs 16 are provided between the base plate 11 and the reinforcing wall 14. These reinforcing ribs 16 are evenly distributed circumferentially and are triangular in shape. One right-angled side of the reinforcing rib 16 is connected to the base plate 11, and the other right-angled side is connected to the reinforcing wall 14, further strengthening the structural strength of the sheath 1. The triangular reinforcing rib 16 saves raw materials while meeting the same strength requirements. It increases the contact area with the base plate 11, dispersing pressure and making it more stable and reliable. Furthermore, the reinforcing rib uses less material, and the stainless steel shell experiences less thermal expansion and contraction during high-temperature annealing, ensuring that the finished core dimensions meet design requirements. Figure 6 and Figure 7 As shown, the transformer core also includes a compensation reactor 3 (i.e., a compensation coil) disposed inside the casing 1. The compensation reactor 3 is disposed between the reinforcing wall 14 and the outer wall 13. That is, the reinforcing wall 14 separates the amorphous strip 4 and the compensation reactor 3, ensuring that the amorphous strip 4 is not affected by the external force of the compensation reactor 3, and avoiding deformation or damage to the amorphous strip 4 after being subjected to external force, which would lead to deterioration of the excitation characteristics and failure to meet the technical requirements.

[0062] The compensating reactor 3 is designed as a small coil with a suitable outer diameter and height according to parameter requirements. Its small size allows it to be placed inside the iron core, making it invisible from the outside. When metering and measuring coils in ultra-high voltage current transformers require a certain instrument safety factor, the compensating reactor 3 can be used to adjust the instrument safety factor and error. The arc-shaped plate 2 corresponding to the compensating reactor 3 is provided with outlet holes 21 for the leads of the compensating reactor 3 to pass through (e.g., ...). Figure 2 and Figure 5 As shown in the figure, for easy wiring, the leads of the compensating reactor 3 include a first lead 31 and a last lead 32.

[0063] In use, the ultra-high voltage current transformer coil is designed according to parameters, specifying the core casing size and the filling size of the amorphous strip 4. The amorphous strip 4 is located within the filling area, with its height 2mm lower than the top of the stainless steel casing 1. A reinforcing wall 14 is added between the inner wall 12 and the outer wall 13 of the stainless steel casing 1, with 8 reinforcing ribs 16 evenly distributed around its circumference. When the coil is subjected to assembly pressure, the reinforcing wall 14 and the reinforcing ribs 16 prevent the amorphous strip 4 from being compressed, thus ensuring that the coil error test is qualified. Four arc-shaped plates 2 are placed on top of the stainless steel casing according to the concave-convex mating arrangement. After the small coil of the compensating reactor is wound according to the design requirements, the perforated arc-shaped plate 2 is removed, and the compensating reactor 3 is placed in the gap between the reinforcing wall 14 and the outer wall 13, and glued to the bottom plate 11 of the casing 1. The lead wire of the compensating reactor 3 is led out from the outlet hole 21, and then the perforated arc-shaped plate 2 is put back in its original position. Finally, based on this, according to the design requirements, the electromagnetic wire 5 and insulating material are wound to form the transformer coil, such as... Figure 8 As shown, the electromagnetic wire 5 has a coil head lead 51 and a coil tail lead 52, which facilitates connection with the head lead 31 and tail lead 32 of the compensating reactor 3.

[0064] The present invention integrates the compensating reactor 3 inside the housing 1, that is, the compensating reactor 3 is directly integrated into the transformer core. The compensating reactor 3 can be directly connected to the electromagnetic wire 5 wound around the outside of the transformer core, that is, the two can be pre-connected. In this way, only the transformer coil needs to be wired in the control cabinet, which is more convenient. Moreover, the compensating reactor no longer occupies space in the control cabinet.

[0065] In other embodiments of the transformer core: depending on the specific design parameters of the core, the distance between the reinforcing wall and the outer wall can also be equal to the distance between the inner wall and the reinforcing wall.

[0066] In other embodiments of the transformer core: the number of reinforcing ribs can be adjusted according to actual needs. Of course, reinforcing ribs may not be provided between the base plate and the reinforcing wall.

[0067] In other embodiments of the transformer core: the casing may not include the reinforcing wall, and the core and the compensating reactor are both disposed between the inner wall and the outer wall.

[0068] In other embodiments of the transformer core: the protrusions and grooves on the arc plate can also be T-shaped or dovetail-shaped.

[0069] In other embodiments of the transformer core: no protrusions or grooves are provided on the arc plate, and both ends of the arc plate are straight.

[0070] In other embodiments of the transformer core, the lead hole can also be located on the protective casing.

[0071] In other embodiments of the transformer core: the number of arc plates can be adjusted according to actual needs. Of course, the cover plate may not be formed by splicing multiple separate arc plates, but by an integral ring plate.

[0072] In other embodiments of the transformer core: the transformer core can also be applied to voltage transformers that require compensation.

[0073] An example of the implementation of the current transformer coil in this invention is... Figure 8 As shown, it includes a current transformer core and an electromagnetic wire wound around the outside of the current transformer core. The specific structure of the current transformer core is the same as that of the current transformer core in the above embodiment, and will not be repeated here.

[0074] The embodiment of the current transformer in this invention is as follows: The current transformer includes a current transformer housing and a transformer coil disposed inside the current transformer housing. The transformer coil includes a transformer core and an electromagnetic wire wound around the outside of the transformer core. The specific structure of the transformer core is the same as that of the transformer core in the above embodiment, and will not be repeated here.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A current transformer, comprising a current transformer housing and a current transformer coil disposed within the current transformer housing, the current transformer coil comprising a current transformer core and an electromagnetic wire wound around the outside of the current transformer core, the current transformer core comprising a protective shell, a core body disposed within the protective shell, and a cover plate cooperating with the protective shell to form a sealed cavity, characterized in that: The transformer core also includes a compensating reactor installed inside the housing to compensate for the instrument's safety factor and error. The housing or cover plate has outlet holes for the lead wires of the compensating reactor to pass through. The lead wires of the compensating reactor are directly connected to the electromagnetic wire wound around the outside of the transformer core. The housing includes a base plate and an inner wall, an outer wall, and a reinforcing wall connected to the base plate. The reinforcing wall is located between the inner wall and the outer wall. The core is installed between the inner wall and the reinforcing wall. The distance between the reinforcing wall and the outer wall is greater than the distance between the inner wall and the reinforcing wall. The compensating reactor is a small compensating coil installed between the reinforcing wall and the outer wall with an outer diameter smaller than the distance between the reinforcing wall and the outer wall.

2. The current transformer of claim 1, characterized in that: Both the protective shell and the cover plate are circular, with the cover plate being formed by splicing together at least two arc-shaped plates.

3. The current transformer of claim 2, wherein: The outlet hole is located on the arc-shaped plate corresponding to the compensating reactor.

4. The current transformer of claim 2, wherein: One of the two adjacent curved plates has a protrusion, and the other curved plate has a groove that matches the shape of the protrusion so that the protrusion can be inserted.

5. The current transformer of claim 4, characterized in that: Both the protrusions and the grooves are semi-circular.

6. The current transformer according to any one of claims 1 to 5, characterized in that: A reinforcing rib is provided between the base plate and the reinforcing wall. The reinforcing rib is triangular, with one right-angled side connected to the base plate and the other right-angled side connected to the reinforcing wall.

7. A transformer coil of a current transformer, comprising a transformer core and a magnetic wire wound outside the transformer core, the transformer core comprising a sheath, a core body arranged inside the sheath, and a cover plate cooperating with the sheath to form a sealed cavity, characterized in that: The transformer core also includes a compensating reactor installed inside the housing to compensate for the instrument's safety factor and error. The housing or cover plate has outlet holes for the lead wires of the compensating reactor to pass through. The lead wires of the compensating reactor are directly connected to the electromagnetic wire wound around the outside of the transformer core. The housing includes a base plate and an inner wall, an outer wall, and a reinforcing wall connected to the base plate. The reinforcing wall is located between the inner wall and the outer wall. The core is installed between the inner wall and the reinforcing wall. The distance between the reinforcing wall and the outer wall is greater than the distance between the inner wall and the reinforcing wall. The compensating reactor is a small compensating coil installed between the reinforcing wall and the outer wall with an outer diameter smaller than the distance between the reinforcing wall and the outer wall.

8. The transformer coil of a current transformer according to claim 7, characterized in that, Both the protective shell and the cover plate are circular, with the cover plate being formed by splicing together at least two arc-shaped plates.

9. The transformer coil of a current transformer according to claim 8, characterized in that, The outlet hole is located on the arc-shaped plate corresponding to the compensating reactor.

10. The transformer coil of a current transformer according to claim 8, characterized in that, One of the two adjacent curved plates has a protrusion, and the other curved plate has a groove that matches the shape of the protrusion so that the protrusion can be inserted.

11. The transformer coil of a current transformer according to claim 10, characterized in that, Both the protrusions and the grooves are semi-circular.

12. The transformer coil of any one of claims 7-11, wherein, A reinforcing rib is provided between the base plate and the reinforcing wall. The reinforcing rib is triangular, with one right-angled side connected to the base plate and the other right-angled side connected to the reinforcing wall.

13. A transformer core of a current transformer comprising a housing, a core arranged within the housing, and a cover plate cooperating with the housing to form a sealed cavity, characterized in that: The transformer core also includes a compensating reactor installed inside the housing to compensate for the instrument's safety factor and error. The housing or cover plate has outlet holes for the lead wires of the compensating reactor to pass through, so that the lead wires of the compensating reactor can be directly connected to the electromagnetic wire wound around the outside of the transformer core. The housing includes a base plate and an inner wall, an outer wall, and a reinforcing wall connected to the base plate. The reinforcing wall is located between the inner wall and the outer wall. The core is installed between the inner wall and the reinforcing wall. The distance between the reinforcing wall and the outer wall is greater than the distance between the inner wall and the reinforcing wall. The compensating reactor is a small compensating coil installed between the reinforcing wall and the outer wall with an outer diameter smaller than the distance between the reinforcing wall and the outer wall.

14. The transformer core of a current transformer according to claim 13, characterized by: Both the protective shell and the cover plate are circular, with the cover plate being formed by splicing together at least two arc-shaped plates.

15. The transformer core of a current transformer according to claim 14, characterized by: The outlet hole is located on the arc-shaped plate corresponding to the compensating reactor.

16. The transformer core of a current transformer according to claim 14, characterized by: One of the two adjacent curved plates has a protrusion, and the other curved plate has a groove that matches the shape of the protrusion so that the protrusion can be inserted.

17. The transformer core of claim 16, wherein: Both the protrusions and the grooves are semi-circular.

18. A transformer core for a current transformer according to any one of claims 13 to 17, characterised in that: A reinforcing rib is provided between the base plate and the reinforcing wall. The reinforcing rib is triangular, with one right-angled side connected to the base plate and the other right-angled side connected to the reinforcing wall.

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