A current transformer with one terminal connection

Abstract

The utility model relates to electric power equipment technical field provides a current transformer of primary wiring end connection, including mutual inductor body, primary coil, primary wiring end, primary fixed block and fastening screw, the primary fixed block fixedly arranged on mutual inductor body is equipped with mounting groove, the primary wiring end with the end of primary coil is connected and is contained in mounting groove, the fastening screw with primary fixed block is detachably connected, and the primary wiring end is pressed and fixed in mounting groove, and the primary wiring end, the end of primary coil and primary fixed block form electric connection between through mechanical pressure. The utility model adopts mechanical pressure connection mode, solved the problem that traditional welding connection is not firm, process is complex, and the maintenance is inconvenient, realized the unity of high reliability, easy maintenance and excellent electrical performance.

Description

Technical Field

[0001] This utility model relates to the field of power equipment technology, and specifically to a current transformer with primary terminal connection. Background Technology

[0002] Current transformers are critical devices in power systems used for current transformation, electrical isolation, and measurement protection. Their primary side needs to be reliably connected to high-voltage lines. Currently, the connection between the primary coil (primary conductor) of a current transformer and the external line is mostly achieved through welding, for example, welding the primary terminals to the primary coil and then fixing the terminals to the terminal blocks with bolts. This welding connection has several drawbacks: 1. Appearance defects: Undercut, weld beads, arc craters, dents and burrs are prone to occur, affecting the appearance and performance of the product.

[0003] 2. Internal defects: They are prone to problems such as porosity, slag inclusion, incomplete penetration or lack of fusion, which affect the mechanical strength and conductivity of the joint.

[0004] 3. Hazardous defects: Under the action of electric current and mechanical stress, cracks or even burn-through may occur, causing major safety accidents.

[0005] 4. Process defects: These can easily lead to incorrect weld dimensions or weld deformation, and require highly skilled operators, making quality control difficult. Furthermore, welding creates permanent connections, making subsequent maintenance or replacement extremely inconvenient.

[0006] Therefore, there is an urgent need for a primary-end connection method that is reliable, easy to install, and easy to maintain. Utility Model Content

[0007] In view of this, the purpose of this utility model is to propose a current transformer with a primary terminal connection, which adopts a mechanical crimping method to solve the problems of weak traditional welding connection, complex process and inconvenient maintenance, and achieves a combination of high reliability, easy maintenance and excellent electrical performance.

[0008] To achieve the above objectives, this utility model provides the following technical solution: This utility model provides a current transformer with a primary terminal connection, including a transformer body, a primary coil, a primary terminal, a primary fixing block, and fastening screws. The primary fixing block is fixedly disposed on the transformer body and has a mounting groove. The primary terminal is connected to the end of the primary coil and is accommodated in the mounting groove. The fastening screw is detachably connected to the primary fixing block and presses the primary terminal into the mounting groove, forming an electrical connection between the primary terminal, the end of the primary coil, and the primary fixing block through mechanical pressure.

[0009] As a further embodiment of this utility model, it also includes a pressure block, which is detachably connected to the primary fixing block by the fastening screw. The contact surface between the pressure block and the primary terminal is plated with a silver conductive layer, and / or the contact surface between the mounting groove and the primary terminal is plated with a silver conductive layer.

[0010] As a further embodiment of this utility model, the fastening screw is an internal hexagon head screw.

[0011] As a further embodiment of this utility model, the number of fastening screws is at least two, symmetrically arranged at both ends of the pressure block.

[0012] As a further embodiment of this utility model, the primary terminal is a flat plate structure, and the shape of the primary terminal is adapted to the mounting groove and the pressing surface of the pressure block.

[0013] As a further embodiment of this utility model, the primary fixing block is made of a high-strength conductive metal material, wherein the conductive metal material is copper or a copper alloy.

[0014] As a further embodiment of this utility model, the pressing block is elongated, and the cross-section of the pressing block is inverted U-shaped or flat.

[0015] As a further embodiment of this utility model, the primary fixing block is fixed to the transformer body by bolt connection or insert injection molding.

[0016] As a further embodiment of this utility model, the current transformer also includes an anti-loosening component, which is disposed on the fastening screw to prevent it from loosening; the anti-loosening component is a combination of spring washer, spring washer and flat washer or thread anti-loosening adhesive.

[0017] As a further embodiment of this utility model, the primary coil is made of soft copper stranded wire, the primary coil is connected to the coil inside the transformer body, and the end of the primary coil is fixedly connected to the primary terminal by cold pressure welding, riveting or welding.

[0018] As a further embodiment of this utility model, the bottom of the mounting groove is provided with a raised rib, and the corresponding position of the primary terminal is provided with a groove that engages with the raised rib, so as to enhance the mechanical stability of the connection.

[0019] As a further embodiment of this utility model, the pressure block is made of a high-strength conductive metal material, wherein the conductive metal material is copper or a copper alloy.

[0020] As a further embodiment of this utility model, the primary terminal is provided with mounting holes for connecting external cables or copper busbars.

[0021] As a further embodiment of this utility model, the primary terminal and the outside of the primary coil, which are fixed by the primary fixing block on the transformer body, are further provided with a resin casting layer.

[0022] Compared with the prior art, the current transformer with primary terminal connection proposed in this utility model has the following advantages: This invention employs mechanical crimping instead of traditional welding, achieving a primary terminal connection with high reliability, low contact resistance, strong vibration resistance, convenient installation, and easy maintenance. It effectively solves various quality defects and maintenance problems caused by welding processes. By applying a large and constant vertical clamping force through pressure blocks and fastening screws, this invention effectively breaks down the oxide film on the surface of the primary terminal, allowing metal atoms to come into close contact and forming a low-resistance, high-current-carrying conductive path. The mechanical crimping method avoids internal defects such as porosity, slag inclusions, and incomplete fusion that can occur with welding, as well as harmful defects such as cracks and burn-through. This results in a stable and reliable electrical connection, ensuring the measurement accuracy and long-term operational stability of the current transformer.

[0023] The pressure block connection structure of this utility model also uses the pre-tightening force generated by the threaded pair to firmly lock the primary terminal into the mounting groove of the fixing block, forming a connection point with extremely high mechanical strength. Electrical conduction is achieved through mechanical interlocking generated by the plastic deformation of the metal, eliminating the need for a heat source or solid-state bonding process with solder. This significantly simplifies the process flow, improves assembly efficiency, and reduces production costs, making it ideal for industrial mass production. When it is necessary to replace the current transformer or inspect the connection point, the pressure block can be removed simply by loosening the fastening screws, making the operation simple and quick. It perfectly balances and improves electrical performance, mechanical strength, production efficiency, ease of maintenance, and safety and reliability, comprehensively solving the various defects and problems inherent in traditional welding connection methods, and providing an advanced and superior primary terminal connection solution for current transformers.

[0024] These or other aspects of this application will become more apparent from the following description of embodiments. It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the application. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or related technologies, the accompanying drawings used in the description of the exemplary embodiments or related technologies will be briefly introduced below. The drawings are used to provide a further understanding of this utility model and constitute a part of the specification. They are used together with the embodiments of this utility model to explain this utility model and do not constitute a limitation on this utility model.

[0026] In the attached diagram: Figure 1This is a structural diagram of a current transformer with primary terminal connections according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the primary terminal of a current transformer with a primary terminal connection according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the installation of a current transformer with a primary winding terminal connected to a primary fixing block in an embodiment of the present invention.

[0027] Marked in the image: 1-Inductor body, 2-Primary coil, 3-Primary terminal, 4-Primary fixing block, 5-Pressure block, 6-Fastening screw, 7-Mounting groove, 8-Wire coil, 9-Resin casting layer. Detailed Implementation

[0028] The present application will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model are further described in detail below with reference to specific examples and the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit this application.

[0030] It should be noted that all uses of "first" and "second" in the embodiments of this utility model are for the purpose of distinguishing two different entities or different parameters with the same name. Therefore, "first" and "second" are merely for convenience of expression and should not be construed as limiting the embodiments of this utility model. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as other steps or units inherent in a process, method, system, product, or device that includes a series of steps or units.

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0033] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] See Figures 1 to 3 As shown, an embodiment of this utility model provides a current transformer with a primary terminal connection, including a transformer body 1, a primary coil 2, a primary terminal 3, a primary fixing block 4, and a fastening screw 6. The primary fixing block 4 is fixedly disposed on the transformer body 1 and has a mounting groove 7. The primary terminal 3 is connected to the end of the primary coil 2 and is accommodated in the mounting groove 7. The fastening screw 6 is detachably connected to the primary fixing block 4 and presses the primary terminal 3 into the mounting groove 7, forming an electrical connection between the primary terminal 3, the end of the primary coil 2, and the primary fixing block 4 through mechanical pressure.

[0035] In some embodiments, the current transformer connected to the primary terminal further includes a pressure block 5, which is detachably connected to the primary fixing block 4 via the fastening screws 6. The contact surface between the primary terminal 3 and the pressure block 5 and / or the mounting groove 7 is plated with a silver conductive layer. There are at least two fastening screws 6, symmetrically arranged at both ends of the pressure block 5, and the fastening screws 6 are socket head cap screws.

[0036] In this embodiment, the primary terminal 3 has a flat plate structure, and its shape is adapted to the pressing surface of the mounting groove 7 and the pressing block 5. The bottom of the mounting groove 7 is provided with raised ribs, and the corresponding position of the primary terminal 3 is provided with a groove that engages with the raised ribs to enhance the mechanical stability of the connection.

[0037] In some embodiments, the primary fixing block 4 and the pressure block 5 are made of a high-strength conductive metal material, such as copper or a copper alloy. The primary fixing block 4 is fixed to the transformer body 1 by bolt connection or insert injection molding. The pressure block 5 is elongated, and its cross-section is an inverted U-shape or a flat plate.

[0038] In this embodiment, the current transformer further includes an anti-loosening component, which is disposed on the fastening screw 6 to prevent it from loosening; the anti-loosening component is a combination of spring washer, spring washer and flat washer or thread anti-loosening adhesive.

[0039] In this invention, the rotational torque of the fastening screw 6 is converted into a large, constant clamping force in the vertical direction, thereby achieving solid-state bonding and electrical connection of the primary circuit conductor. During operation, when the fastening screw 6 is tightened using an Allen wrench, its rotational motion is converted into an axial linear tensile force. This linear tensile force is transmitted and redistributed through the pressure block 5. The pressure block 5 transforms the concentrated force generated by the fastening screw 6 into uniform pressure, applied to the upper surface of the primary terminal 3. This enormous pressure causes microscopic plastic deformation between the primary terminal 3 and the bottom surface of the mounting groove 7 of the primary fixing block 4. The contacting metal surfaces interlock under high pressure, forming a strong mechanical lock with high resistance to vibration and loosening. During electrical conduction, the high voltage destroys the oxide film and other insulating layers on the conductor surface, allowing pure metal atoms to come into close contact, enabling smooth electron flow and forming a low-resistance, high-reliability electrical path. The silver conductive layer on the contact surface further fills the microscopic gaps, optimizing conductivity.

[0040] In this embodiment, the primary coil 2 is made of soft copper stranded wire. The primary coil 2 is connected to the coil 8 inside the transformer body 1. The end of the primary coil 2 is fixedly connected to the primary terminal 3 by cold pressure welding, riveting or welding.

[0041] In this embodiment, the primary terminal 3 is provided with mounting holes for connecting external cables or copper busbars. The primary terminal 3 and the primary coil 2, which are fixed to the transformer body 1 by the primary fixing block 4, are also provided with a resin casting layer 9.

[0042] The current transformer connected to the primary terminal of this utility model forms a complete conductive circuit through the transformer body 1, primary coil 2, primary terminal 3, primary fixing block 4 and fastening screw 6. The primary current of the circuit under test is introduced through the external cable or copper busbar connected to the primary terminal 3. The current flows sequentially through the primary terminal 3, primary fixing block 4, primary coil 2, electromagnetic unit (i.e. coil 8) inside the transformer, primary coil 2 at the other end, primary fixing block 4 at the other end, and primary terminal 3 at the other end before flowing out. The connection structure protected by this utility model ensures the electrical continuity of the two key connection points of the terminal and the fixing block in this circuit, forming a high-reliability electrical connection point with constant voltage, low resistance, vibration resistance and maintenance-free operation.

[0043] For example, when the current transformer with the primary terminal connected in this utility model is applied to current measurement and protection in a 10kV power distribution system, the transformer body 1 of the standard medium-voltage current transformer is an epoxy resin casting structure, and the primary coil 2 is made of a material with a cross-sectional area of ​​10 mm². 2The primary coil 2 is made of soft copper stranded wire, and its end is fixed to the primary terminal 3 by cold pressure welding. The primary terminal 3 is a 3mm thick T2 copper plate with a silver-plated surface and has a 10mm diameter mounting hole for connecting external cables. The primary fixing block 4 and the pressure block 5 are both made of T2Y2 copper. The primary fixing block 4 is fixed to the frame inside the transformer body 1 by stainless steel bolts. The mounting groove 7 on the primary fixing block 4 has two parallel raised ribs at the bottom, and the corresponding position of the primary terminal 3 has a matching groove. Two 8.8 grade socket head cap screws are used as fastening screws 6, and spring washers are used to prevent loosening. The fastening screws 6 are M6 size.

[0044] During installation, place the primary terminal 3 into the mounting slot 7, ensuring the ribs engage with the grooves. Cover with the pressure block 5, insert and initially tighten the two Allen screws by hand. Finally, use a torque wrench to symmetrically and gradually tighten the two fastening screws 6 to a preset torque of 25 N·m. The connection point contact resistance is less than 5 μΩ, installation is faster than traditional welding, and the transformer can be easily disassembled for future maintenance and replacement.

[0045] This invention employs mechanical crimping instead of traditional welding, achieving a primary terminal connection with high reliability, low contact resistance, strong vibration resistance, convenient installation, and easy maintenance. It effectively solves various quality defects and maintenance problems caused by welding processes. By applying a large and constant vertical clamping force through the pressure block 5 and fastening screw 6, this invention effectively breaks down the oxide film on the surface of the primary terminal 3, allowing metal atoms to come into close contact and forming a low-resistance, high-current-carrying conductive path. The mechanical crimping method avoids internal defects such as porosity, slag inclusions, and lack of fusion that may occur during welding, as well as harmful defects such as cracks and burn-through. This results in a stable and reliable electrical connection, ensuring the measurement accuracy and long-term operational stability of the current transformer.

[0046] The pressure block 5 connection structure of this utility model also securely locks the primary terminal 3 into the mounting groove 7 of the fixing block through the pre-tightening force generated by the threaded pair, forming a connection point with extremely high mechanical strength. Electrical conduction is achieved through mechanical interlocking generated by the plastic deformation of the metal, eliminating the need for a heat source or solid-state bonding process with solder. This significantly simplifies the process flow, improves assembly efficiency, and reduces production costs, making it ideal for industrial mass production. When it is necessary to replace the current transformer or inspect the connection point, the pressure block 5 can be removed simply by loosening the fastening screw 6, making the operation simple and quick. It perfectly balances and improves electrical performance, mechanical strength, production efficiency, ease of maintenance, and safety and reliability, comprehensively solving the various defects and problems inherent in traditional welding connection methods, and providing an advanced and superior primary terminal connection solution for current transformers.

[0047] The above are exemplary embodiments disclosed in this utility model. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this utility model as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this utility model may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0048] It should be understood that, as used herein, the singular form "a" is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations of one or more of the associatedly listed items. The embodiment numbers disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0049] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Within the framework of the present invention, technical features of the above embodiments or different embodiments can also be combined, and many other variations of different aspects of the present invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A current transformer with primary terminal connection, comprising a transformer body (1), a primary coil (2), a primary terminal (3), a primary fixing block (4), and fastening screws (6); characterized in that: The primary fixing block (4) is fixedly installed on the transformer body (1) and has a mounting groove (7); the primary terminal (3) is connected to the end of the primary coil (2) and accommodated in the mounting groove (7); the fastening screw (6) is detachably connected to the primary fixing block (4) and presses the primary terminal (3) into the mounting groove (7), and forms an electrical connection between the primary terminal (3), the end of the primary coil (2) and the primary fixing block (4) by mechanical pressure.

2. A current transformer for a one terminal connection as claimed in claim 1, characterized in that It also includes a pressure block (5), which is detachably connected to the primary fixing block (4) by the fastening screw (6). The contact surface between the pressure block (5) and the primary terminal (3) is plated with a silver conductive layer, and / or the contact surface between the mounting groove (7) and the primary terminal (3) is plated with a silver conductive layer.

3. A current transformer for a one terminal connection as claimed in claim 2, characterised in that, The primary terminal (3) has a flat plate structure, and the shape of the primary terminal (3) is adapted to the pressing surface of the mounting groove (7) and the pressing block (5).

4. A current transformer for a one terminal connection as claimed in claim 3, characterised in that, The fastening screw (6) is an internal hexagonal head screw; the number of the fastening screw (6) is at least two, symmetrically arranged at both ends of the pressure block (5).

5. A current transformer for a terminal connection of a primary circuit, according to claim 4, characterized in that, Both the primary fixing block (4) and the pressure block (5) are made of conductive metal material.

6. A current transformer for a one terminal connection as claimed in claim 5, characterised in that, The primary fixing block (4) is fixed to the transformer body (1) by bolt connection or insert injection molding.

7. A current transformer for a one terminal connection as claimed in claim 1, characterized in that The primary coil (2) is made of soft copper stranded wire. The primary coil (2) is connected to the coil (8) inside the transformer body (1). The end of the primary coil (2) is fixedly connected to the primary terminal (3) by cold pressure welding, riveting or welding.

8. A current transformer for a one terminal connection as claimed in claim 3, characterised in that, The bottom of the mounting groove (7) is provided with raised ribs, and the corresponding position of the primary terminal (3) is provided with a groove that engages with the raised ribs.

9. A current transformer for a terminal connection of a primary circuit, according to claim 8, characterized in that, The primary terminal (3) is provided with mounting holes for connecting external cables or copper busbars.

10. A current transformer for a terminal connection of a primary circuit, as claimed in claim 1, characterized in that, The transformer body (1) is provided with a resin casting layer (9) on the outside of the primary terminal (3) and the primary coil (2) which are fixed by the primary fixing block (4).

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