A method for manufacturing a current-voltage Y-type combined mutual inductor

Abstract

The application discloses a current-voltage Y-type combined mutual inductor manufacturing method, relates to the technical field of mutual inductors, and comprises the following steps: positioning each current body in a pouring mold; fixing each voltage device at a predetermined position of the pouring mold; connecting a primary connecting wire of a first high-voltage end of a voltage primary winding with a corresponding-phase current primary high-voltage conducting row; twisting and connecting second high-voltage ends of voltage primary windings of each phase to form Y-type wiring and then connecting to a primary N end; connecting secondary leads of each body on corresponding secondary wiring terminals according to corresponding marks; twisting and connecting secondary n ends of each voltage body as a common end to form Y-type wiring and then connecting to n ends of secondary wiring terminals; adjusting the spacing between each component and then performing vacuum pouring to form a main insulator; and sleeving a high-temperature vulcanized silicon rubber sleeve on the outer surface of the main insulator; the method makes a significant breakthrough in structural design, electromagnetic performance, installation and maintenance, insulation protection and the like, and improves the manufacturing level of the combined mutual inductor.

Description

Technical Field

[0001] This invention relates to the field of instrument transformer technology, and specifically to a method for manufacturing a current-voltage Y-type combined instrument transformer. Background Technology

[0002] In power systems, current-voltage combined instrument transformers are key equipment for energy metering, relay protection, and monitoring and control, and their performance directly affects the reliability and safety of power grid operation. However, existing outdoor combined instrument transformers generally suffer from the following technical defects, which seriously restrict the efficient and stable operation of power equipment:

[0003] 1. Traditional combined instrument transformers are bulky and require a large installation space, making them difficult to adapt to, especially in urban power grids or compact substations. Furthermore, the split design requires additional connecting components, further increasing structural complexity.

[0004] 2. Older instrument transformers often use oil-immersed insulation, which is prone to oil leakage due to seal aging during long-term operation. This not only pollutes the environment but may also lead to decreased insulation performance or even short circuits. The significant volume change of the oil medium under extreme temperature differences further exacerbates the risk of seal failure.

[0005] 3. In outdoor environments, the surface of instrument transformers is prone to accumulating contaminants (such as salt spray and dust), which can easily lead to flashover accidents under humid conditions. In addition, the exposed design of high-voltage terminals lacks protection, further increasing the risk of leakage and flashover.

[0006] 4. The existing transformer core materials and coil manufacturing processes are outdated, resulting in insufficient dynamic and thermal stability under short-circuit current and a tendency for magnetic saturation under high-current conditions. Simultaneously, the low capacity of the secondary winding makes it difficult to meet the high load requirements of smart grids for multiple signal outputs (such as the synchronization needs of metering, protection, and monitoring).

[0007] 5. Existing instrument transformers lack intelligent identification methods, requiring manual verification of nameplates or consultation of paper records during maintenance, which is time-consuming and prone to errors. Fault location relies on power outage detection, resulting in high maintenance costs, and oil-immersed structures require re-oiling and sealing after maintenance, making the process cumbersome.

[0008] 6. Voltage transformers are prone to ferroresonance when the power grid is operating asymmetrically or during switching operations. Traditional designs lack effective resonance suppression measures, which may cause overvoltage damage to equipment or malfunction of protection systems. Summary of the Invention

[0009] The purpose of this invention is to provide a method for manufacturing a Y-type current and voltage combined transformer, which achieves significant breakthroughs in structural design, electromagnetic performance, installation and maintenance, and insulation protection, thereby improving the manufacturing level of combined transformers. It is particularly suitable for smart grid construction and power metering and protection applications in harsh environments.

[0010] To achieve the above objectives, the technical solution of this application is: a method for manufacturing a current-voltage Y-type combined transformer, comprising:

[0011] The process of fixing the current transformer body: The current transformer body A, current transformer body B, and current transformer body C are respectively positioned in the casting mold through the corresponding secondary brackets of current phase A, current phase B, and current phase C.

[0012] Voltage transformer body A, voltage transformer body B, and voltage transformer body C are fixed in the predetermined position of the casting mold using voltage transformer body clamps;

[0013] Electrical connection procedure: Connect the primary connection line of the first high voltage terminal of the primary voltage winding to the primary high voltage busbar of the corresponding phase. The exposed part of the connection is wrapped with semi-conductive rubber tape to achieve effective shielding of the high voltage electric field.

[0014] The second high-voltage terminals of the primary windings of each phase are twisted together to form a Y-type connection and then connected to the primary N terminal.

[0015] Secondary wiring procedure: The secondary leads of current transformer body A, current transformer body B, current transformer body C, voltage transformer body A, voltage transformer body B, and voltage transformer body C are connected to the secondary terminals according to their corresponding markings.

[0016] Connect the secondary n terminals of voltage transformer body A, voltage transformer body B, and voltage transformer body C as a common terminal by twisting them together to form a Y-type connection, and then connect it to the n terminal of the secondary terminal.

[0017] Insulation molding process: After adjusting the spacing between each component, epoxy resin is used for vacuum casting to form the main insulator;

[0018] A high-temperature vulcanized silicone rubber sleeve is molded onto the outer surface of the main insulator, and the two are bonded and fixed together using a single-component silicone rubber adhesive.

[0019] The assembled product is placed in a constant temperature and humidity treatment room to complete the curing process.

[0020] As a preferred embodiment of the present invention, the manufacturing method of the current transformer body A, current transformer body B, and current transformer body C is as follows:

[0021] Iron core insulation treatment: The current iron core is subjected to multi-layer insulation treatment, which consists of wrapping the insulation layer cardboard corner ring, twill cloth tape insulation layer, polyurethane board buffer layer, and then half-lapping a layer of self-adhesive tape from the inside out.

[0022] Secondary winding fabrication: Enamelled round copper wire is wound on the current core after insulation treatment to form a secondary current winding. After a polyester film is half-lapped on the outer layer of the secondary winding, a shaped copper foil or shaped aluminum foil is added.

[0023] Bracket installation: After fixing and installing the secondary brackets for current phase A, current phase B, and current phase C, half-overlap a layer of semi-conductive corrugated paper shielding layer;

[0024] Primary winding fabrication: The primary current winding is wound through the current iron core, and a high-voltage busbar is welded to both ends of the primary current winding.

[0025] Primary winding insulation treatment: The primary winding is subjected to multi-layer insulation treatment, from the inside to the outside, a layer of twill tape is half-stacked, a layer of crepe paper is half-stacked, and a layer of semi-conductive crepe paper is half-stacked.

[0026] Body forming: After completing the above processes, the current transformer body is formed into three phase units A, B, and C.

[0027] As a preferred embodiment of the present invention, the manufacturing method of the voltage transformer body A, voltage transformer body B, and voltage transformer body C is as follows:

[0028] Insulation layer preparation: A layer of insulating paperboard is rolled on the skeleton substrate, and multiple layers of PMP composite paper are stacked to form a basic insulation layer;

[0029] Secondary winding fabrication: A voltage secondary winding is wound outside the basic insulation layer. PMP composite paper is added between the layers of the secondary winding as interlayer insulation. Semi-conductive corrugated paper is wrapped around the outer layer of the winding to form a low-voltage shielding layer.

[0030] Skeleton assembly: Fix the resin skeleton on the CNC parallel winding machine, and add molded copper foil and semi-conductive crepe paper to the outside of the resin skeleton to form an inner shielding layer.

[0031] Primary winding fabrication: Multiple layers of DMD insulating paper are added outside the inner shielding layer before winding the primary voltage winding. After the primary voltage winding is completed, shaped copper foil is added as a shielding layer (with appropriate gaps left at the beginning and end). Semi-conductive crepe paper is wrapped around the outer layer to form a high voltage shielding layer.

[0032] Component assembly: The voltage secondary winding is fitted into the resin frame, and the voltage core is fitted into the voltage secondary winding;

[0033] Core fixing: A metal hose clamp is used to pass through the gap between the outside of the voltage core and the voltage secondary winding, and the voltage core and voltage transformer body clamp are fastened by the positioning thread.

[0034] Iron core insulation treatment: The exposed part of the voltage iron core is treated with multi-layer insulation, from the inside to the outside, in the following order: half-stacked layer of self-adhesive tape insulation layer, molded polyurethane board buffer layer, half-stacked layer of self-adhesive tape insulation layer, outer molded copper foil or aluminum foil, and half-stacked layer of semi-conductive crepe paper to form a low-voltage shielding layer.

[0035] Surface treatment: Apply semi-conductive paint of appropriate width to both sides of the wrapped voltage core;

[0036] Body forming: After completing the above processes, the voltage transformer body is formed into three phase units A, B, and C.

[0037] As a preferred embodiment of the present invention, the secondary support for current phase A and the secondary support for current phase C have the same structure, both including symmetrically arranged angular legs, the top of each angular leg being connected to the side of the first arc-shaped support plate with symmetrically arranged connection points, and the bottom of each angular leg being connected to a first fixing plate.

[0038] As a preferred embodiment of the present invention, the B-phase secondary support includes asymmetrically arranged irregularly shaped legs, the top of each irregularly shaped leg is connected to the side of the second arc-shaped support plate and the connection points are not symmetrically arranged, and the bottom of each irregularly shaped leg is connected to a second fixing plate.

[0039] As a preferred embodiment of the present invention, auxiliary secondary windings are added outside the voltage secondary windings of the voltage transformer body A, voltage transformer body B, and voltage transformer body C. The end wire of the auxiliary secondary winding of voltage transformer body A is connected to the beginning wire of the auxiliary secondary winding of voltage transformer body B, and the end wire of the auxiliary secondary winding of voltage transformer body B is connected to the beginning wire of the auxiliary secondary winding of voltage transformer body C. The beginning wire of the auxiliary secondary winding of voltage transformer body A and the end wire of the auxiliary secondary winding of voltage transformer body C are respectively connected to the corresponding terminals of the auxiliary secondary winding of the main insulator. Before the high-temperature vulcanized silicone rubber sleeve is encapsulated, these two terminals are connected with bare copper wire to form a closed suppression circuit, which can effectively prevent the occurrence of ferroresonance and make the product safer to operate.

[0040] As a preferred embodiment of the present invention, the current transformer body A and the voltage transformer body A, the current transformer body B and the voltage transformer body B, and the current transformer body C and the voltage transformer body C are all arranged in a one-to-one correspondence in the main insulator, resulting in a compact structure.

[0041] As a preferred embodiment of the present invention, the primary high-voltage conductors of the three phases A, B, and C are tilted at an angle and arranged in a V-shape to optimize the electric field distribution.

[0042] As a preferred embodiment of the present invention, a secondary wiring platform is cast in the lower part of the main insulator. The secondary wiring platform has built-in secondary wiring terminals. The secondary wiring terminals are sealed by a secondary rubber gasket and a secondary cover plate. The screws used to fix the secondary cover plate are provided with lead-sealed holes and are fitted with lead seals. This can prevent the theft of electricity by replacing or changing the transformer ratio of the nameplate, and also facilitates the supervision and inspection work of the electricity consumption department. The State Grid special electronic tag is attached to the secondary wiring terminals with silicone and is located above the secondary wiring terminals for easy remote identification.

[0043] As a preferred embodiment of the present invention, the current ratio is permanently marked on the surface of the main insulator by laser etching, which can prevent the theft of electricity by replacing or changing the label ratio, and also facilitates the supervision and inspection work of the electricity user department.

[0044] By adopting the above technical solution, the present invention can achieve the following technical effects:

[0045] 1. An optimized design with a top-to-bottom layered layout is adopted, with the voltage transformer body located at the bottom and the current transformer body at the top, resulting in a more compact structure, effectively reducing the overall size while increasing capacity.

[0046] 2. The coil is made of copper foil or non-magnetic aluminum foil combined with shielding materials such as semi-conductive crepe paper, which effectively suppresses electromagnetic interference between current and voltage units and between adjacent phases, ensuring high-precision measurement and making it suitable for harsh outdoor environments.

[0047] 3. The integrated structural design is adopted during manufacturing. During installation, only the current transformer needs to be fixed and the primary and secondary wiring needs to be completed according to the phase sequence, which greatly saves assembly time.

[0048] 4. By embedding electronic tags (RFID) during the manufacturing process, product information can be quickly obtained through remote scanning during maintenance, eliminating the need for manual verification and significantly reducing maintenance costs.

[0049] 5. The winding uses epoxy resin vacuum casting as the inner insulation and epoxy resin + silicone rubber composite layer as the outer insulation. It has a high withstand voltage rating and stable insulation performance during long-term operation.

[0050] 6. During manufacturing, the three-phase current terminals A, B, and C are arranged in a V-shape to both sides, and multi-level rainproof skirts are distributed on the outer wall of the high-voltage end and the main body to significantly improve the creepage distance.

[0051] 7. A protective cover sealing structure is installed on the three-phase high-voltage end, and the sealing protection is completed during the manufacturing stage, which effectively prevents the accumulation of dirt and the intrusion of rain and snow, and avoids flashover accidents.

[0052] 8. During the manufacturing process, auxiliary secondary windings are added to the three-phase voltage coils A, B, and C, and the start-end connection is adopted (end of phase A → start of phase B, end of phase B → start of phase C, and start of phase A and end of phase C are short-circuited) to eliminate the risk of ferroresonance from the process and ensure the safe operation of the equipment. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a front view of the internal structure of the present invention;

[0055] Figure 2 This is a front view of the external structure of the present invention;

[0056] Figure 3 This is a side view of the external structure of the present invention;

[0057] Figure 4 This is a top view of the external structure of the present invention;

[0058] Figure 5 These are the three-view and three-dimensional diagrams of the AC phase secondary support structure of the present invention;

[0059] Figure 6 These are the three-view and three-dimensional views of the current B-phase secondary support structure of the present invention;

[0060] Figure 7 This is a schematic diagram of the current single-ratio wiring principle of the present invention.

[0061] The components include: 1. Primary high-voltage conductor busbar; 2. Primary current winding; 3. Current core; 4. Secondary current winding; 5. A-phase secondary support; 6. Primary connecting wire; 7. Primary voltage winding; 8. Voltage core; 9. Secondary voltage winding; 10. Voltage transformer body clamp; 11. Secondary terminal block; 12. Main insulator; 13. High-temperature vulcanized silicone rubber sleeve; 14. Base; 15. Secondary cover plate; 16. Secondary rubber pad; 17. Electronic tag; 18. B-phase secondary support; 19. Resin skeleton; 20. Primary N-terminal; 21. Silicone umbrella skirt; 22. Auxiliary secondary platform; 23. First arc-shaped support plate; 24. Angular support leg; 25. First fixing plate; 26. Second arc-shaped support plate; 27. Irregularly shaped support leg; 28. Second fixing plate. Detailed Implementation

[0062] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0065] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0066] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0067] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0068] It should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0069] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0070] Example 1

[0071] Please see Figure 1-7 This embodiment provides a method for manufacturing a current-voltage Y-type combined transformer, including:

[0072] S1. Body fixing process

[0073] S1.1 Position the current transformer body A, current transformer body B, and current transformer body C in the casting mold through the corresponding secondary brackets for current phase A, current phase B, and current phase C, respectively.

[0074] S1.2 The voltage transformer body A, voltage transformer body B, and voltage transformer body C are fixed in the predetermined position of the casting mold using voltage transformer body clamps.

[0075] S2. Electrical connection process

[0076] S2.1 Connect the first high-voltage terminal of the primary voltage winding to the corresponding phase's primary high-voltage busbar via a primary connection line. The exposed part at the connection point is sealed with semi-conductive rubber tape to achieve effective shielding of the high-voltage electric field.

[0077] S2.2 The second high-voltage terminals of the primary windings of each phase are twisted together to form a Y-type connection and then connected to the primary N terminal.

[0078] S3. Secondary wiring process

[0079] S3.1 Connect the secondary leads of current transformer body A, B, C and voltage transformer body A, B, C to the secondary terminals according to their corresponding markings;

[0080] S3.2 Connect the secondary n terminals of voltage transformer bodies A, B, and C as common terminals by twisting them together to form a Y-type connection, and then connect it to the n terminal of the secondary terminal block.

[0081] S4. Insulation forming process

[0082] S4.1 After adjusting the spacing between each component, high-quality epoxy resin is used for vacuum casting to form the main insulator;

[0083] S4.2 A high-temperature vulcanized silicone rubber sleeve is molded onto the outer surface of the main insulator, and the two are bonded and fixed together by a single-component silicone rubber adhesive.

[0084] S4.3 Place the assembled product in a constant temperature and humidity treatment chamber to complete the curing process.

[0085] Preferably, the current and voltage transformer bodies are dried in the layered drying chamber of the cluster vacuum drying equipment, then grouped, fixed, and sealed for preservation to prevent moisture absorption before molding.

[0086] This embodiment achieves standardized production of Y-type current and voltage combined transformers through the above process steps. The product features a compact structure, anti-resonance, and anti-theft characteristics, and is particularly suitable for power metering and protection in three-phase three-wire systems with ungrounded neutral points.

[0087] Example 2

[0088] This embodiment provides a current-voltage Y-type combined transformer, which is manufactured by the method described in Embodiment 1. Specifically, it includes: casting a main insulator consisting of current transformer body A, current transformer body B, current transformer body C, voltage transformer body A, voltage transformer body B, and voltage transformer body C into one piece using epoxy resin, and then fitting a high-temperature vulcanized silicone rubber sleeve on the outer surface of the main insulator to form a composite insulation.

[0089] The upper part of the primary high-voltage conductor of current transformer body A, current transformer body B, and current transformer body C extends out of the main insulator, and the lower part is located inside the main insulator and connected to the first high-voltage terminal of the primary voltage winding of the corresponding voltage transformer body A, voltage transformer body B, and voltage transformer body C. The exposed part of the connection is wrapped with semi-conductive rubber tape.

[0090] The second high-voltage terminals of the primary windings of voltage transformer bodies A, B, and C are twisted together to form a Y-type connection and then connected to the primary N terminal. This primary N terminal is located between phases A and B on the upper rear side of the main insulator.

[0091] The secondary leads of current transformer body A, current transformer body B, current transformer body C, voltage transformer body A, voltage transformer body B, and voltage transformer body C are connected to the secondary terminals according to their corresponding markings.

[0092] The secondary n-terminals of voltage transformer bodies A, B, and C are twisted together as a common terminal to form a Y-type connection, which is then connected to the n-terminal of the secondary terminal block.

[0093] In this embodiment, multiple rainproof skirts are distributed on the upper outer wall of the main insulator, and these skirts surround the lower outer periphery of the primary high-voltage conductor. Silicone skirts are also distributed in the middle and lower parts of the main insulator. This multi-segment umbrella-shaped structure effectively increases the creepage distance, improves insulation performance, and disperses electric field stress through the geometric shape of the skirts, avoiding electric field concentration and improving the overall operational reliability of the equipment.

[0094] In this embodiment, the lower part of the main insulation is recessed inward to form a stepped shape, and the bottom center is a square boss.

[0095] In this embodiment, the primary voltage winding is insulated from the secondary voltage winding by passing through a resin skeleton.

[0096] In this embodiment, the current transformer body A and voltage transformer body A, the current transformer body B and voltage transformer body B, and the current transformer body C and voltage transformer body C are all arranged in a one-to-one correspondence in the main insulator and are electrically connected through a primary connecting line.

[0097] The Y-type combined current and voltage transformer provided by this invention adopts an epoxy resin and silicone rubber composite insulation structure. It optimizes the electric field distribution through double-layer insulation and uses copper foil or non-magnetic aluminum foil combined with semi-conductive crepe paper and other shielding materials to make the coils, effectively suppressing electromagnetic interference between current and voltage units and between adjacent phases, fundamentally solving the technical defects of traditional equipment. The product adopts a Y / Y0 type winding design to achieve a compact structure, and has comprehensive advantages such as excellent resistance to flashover, high dynamic and thermal stability, large secondary capacity, resistance to ultraviolet radiation and wind erosion, long maintenance cycle, and convenient installation, fully meeting the stringent requirements of smart grid outdoor applications. The use of semi-conductive crepe paper and semi-conductive paint on the current and voltage transformer bodies is intended to shield or equalize the electric field, thereby reducing the partial discharge of the combined transformer. The use of copper foil fully considers the mutual influence of electromagnetic fields between current and voltage during operation, ensuring higher stability, reliability, and accuracy of the product's metering.

[0098] During installation and use, only one or two wirings need to be performed according to the phase sequence. Finally, protective covers are installed on the A, B, and C high-voltage terminals for sealing. It has the advantages of small size, large creepage distance, strong anti-interference, high metering accuracy, convenient installation, easy maintenance, stable insulation, and safe operation, which further improves the design and manufacturing level of combined instrument transformers.

[0099] During operation, grounding of the primary neutral (N) terminal is strictly prohibited. Taking a single current transformer as an example, the secondary terminals n, aS2, bS2, and cS2 must be reliably grounded. Open circuits are strictly prohibited on the secondary side of current transformers, and short circuits are strictly prohibited on the secondary side of voltage transformers. The current ratio is laser-etched in a prominent position on the transformer surface. This prevents electricity theft by replacing or tampering with the transformer ratio label and facilitates supervision and inspection by electricity users.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for manufacturing a current-voltage Y-type combined transformer, characterized in that, include: The process of fixing the current transformer body: The current transformer body A, current transformer body B, and current transformer body C are respectively positioned in the casting mold through the corresponding secondary brackets of current phase A, current phase B, and current phase C. Voltage transformer body A, voltage transformer body B, and voltage transformer body C are fixed in the predetermined position of the casting mold using voltage transformer body clamps; Electrical connection procedure: Connect the primary connection line of the first high voltage terminal of the primary voltage winding to the primary high voltage busbar of the corresponding phase. The exposed part of the connection is wrapped with semi-conductive rubber tape to achieve effective shielding of the high voltage electric field. The second high-voltage terminals of the primary windings of each phase are twisted together to form a Y-type connection and then connected to the primary N terminal. Secondary wiring procedure: The secondary leads of current transformer body A, current transformer body B, current transformer body C, voltage transformer body A, voltage transformer body B, and voltage transformer body C are connected to the secondary terminals according to their corresponding markings. Connect the secondary n terminals of voltage transformer body A, voltage transformer body B, and voltage transformer body C as a common terminal by twisting them together to form a Y-type connection, and then connect it to the n terminal of the secondary terminal. Insulation molding process: After adjusting the spacing between each component, epoxy resin is used for vacuum casting to form the main insulator; A high-temperature vulcanized silicone rubber sleeve is molded onto the outer surface of the main insulator, and the two are bonded and fixed together using a single-component silicone rubber adhesive. The assembled product is placed in a constant temperature and humidity treatment room to complete the curing process.

2. The method for manufacturing a Y-type combined current-voltage transformer according to claim 1, characterized in that, The manufacturing methods for the current circuit body A, current circuit body B, and current circuit body C are as follows: Iron core insulation treatment: The current iron core is subjected to multi-layer insulation treatment, which consists of wrapping the insulation layer cardboard corner ring, twill cloth tape insulation layer, polyurethane board buffer layer, and then half-lapping a layer of self-adhesive tape from the inside out. Secondary winding fabrication: Enamelled round copper wire is wound on the current core after insulation treatment to form a secondary current winding. After a polyester film is half-lapped on the outer layer of the secondary winding, a shaped copper foil or shaped aluminum foil is added. Bracket installation: After fixing and installing the secondary brackets for current phase A, current phase B, and current phase C, half-overlap a layer of semi-conductive corrugated paper shielding layer; Primary winding fabrication: The primary current winding is wound through the current iron core, and a high-voltage busbar is welded to both ends of the primary current winding. Primary winding insulation treatment: The primary winding is subjected to multi-layer insulation treatment, from the inside to the outside, a layer of twill tape is half-stacked, a layer of crepe paper is half-stacked, and a layer of semi-conductive crepe paper is half-stacked. Body forming: After completing the above processes, the current transformer body is formed into three phase units A, B, and C.

3. The method for manufacturing a Y-type combined current-voltage transformer according to claim 1, characterized in that, The manufacturing methods for voltage transformer body A, voltage transformer body B, and voltage transformer body C are as follows: Insulation layer preparation: A layer of insulating paperboard is rolled on the skeleton substrate, and multiple layers of PMP composite paper are stacked to form a basic insulation layer; Secondary winding fabrication: A voltage secondary winding is wound outside the basic insulation layer. PMP composite paper is added between the layers of the secondary winding as interlayer insulation. Semi-conductive corrugated paper is wrapped around the outer layer of the winding to form a low-voltage shielding layer. Skeleton assembly: Fix the resin skeleton on the CNC parallel winding machine, and add molded copper foil and semi-conductive crepe paper to the outside of the resin skeleton to form an inner shielding layer. Primary winding fabrication: Multiple layers of DMD insulating paper are added outside the inner shielding layer before winding the primary voltage winding. After the primary voltage winding is completed, shaped copper foil is added as a shielding layer, and semi-conductive corrugated paper is wrapped around the outer layer to form a high voltage shielding layer. Component assembly: The voltage secondary winding is fitted into the resin frame, and the voltage core is fitted into the voltage secondary winding; Core fixing: A metal hose clamp is used to pass through the gap between the outside of the voltage core and the voltage secondary winding, and the voltage core and voltage transformer body clamp are fastened by the positioning thread. Iron core insulation treatment: The exposed part of the voltage iron core is treated with multi-layer insulation, from the inside to the outside, in the following order: half-stacked layer of self-adhesive tape insulation layer, molded polyurethane board buffer layer, half-stacked layer of self-adhesive tape insulation layer, outer molded copper foil or aluminum foil, and half-stacked layer of semi-conductive crepe paper to form a low-voltage shielding layer. Surface treatment: Apply semi-conductive paint to both sides of the wrapped voltage core; Body forming: After completing the above processes, the voltage transformer body is formed into three phase units A, B, and C.

4. The method for manufacturing a current-voltage Y-type combined transformer according to claim 2, characterized in that, The secondary support for phase A current and the secondary support for phase C current have the same structure, both including symmetrically arranged angular legs. The top of each angular leg is connected to the side of the first arc-shaped support plate, and the connection points are symmetrically arranged. The bottom of each angular leg is connected to a first fixing plate.

5. The method for manufacturing a Y-type combined current-voltage transformer according to claim 2, characterized in that, The current B-phase secondary support includes asymmetrically arranged irregularly shaped legs. The top of each irregularly shaped leg is connected to the side of the second arc-shaped support plate, and the connection points are not symmetrically arranged. The bottom of each irregularly shaped leg is connected to a second fixing plate.

6. The method for manufacturing a Y-type combined current-voltage transformer according to claim 1, characterized in that, An auxiliary secondary winding is added outside the voltage secondary windings of the voltage transformer body A, voltage transformer body B, and voltage transformer body C. The end line of the auxiliary secondary winding of voltage transformer body A is connected to the beginning line of the auxiliary secondary winding of voltage transformer body B, and the end line of the auxiliary secondary winding of voltage transformer body B is connected to the beginning line of the auxiliary secondary winding of voltage transformer body C. The beginning line of the auxiliary secondary winding of voltage transformer body A and the end line of the auxiliary secondary winding of voltage transformer body C are respectively connected to the corresponding terminals of the auxiliary secondary winding of the main insulator. Before the high-temperature vulcanized silicone rubber sleeve is encapsulated, the two terminals are connected with bare copper wire to form a closed suppression circuit.

7. The method for manufacturing a Y-type combined current-voltage transformer according to claim 1, characterized in that, The current transformer body A and voltage transformer body A, current transformer body B and voltage transformer body B, and current transformer body C and voltage transformer body C are all arranged in a one-to-one correspondence in the main insulator.

8. The method for manufacturing a current-voltage Y-type combined transformer according to claim 1, characterized in that, The primary high-voltage conductors of phases A, B, and C are tilted at an angle and arranged in a V-shape.

9. The method for manufacturing a Y-type combined current-voltage transformer according to claim 1, characterized in that, A secondary wiring platform is cast in the lower part of the main insulator. The secondary wiring platform has built-in secondary wiring terminals. The secondary wiring terminals are sealed by secondary rubber gaskets and secondary cover plates. The screws used to fix the secondary cover plates are equipped with lead sealing holes and lead seals are installed. The State Grid special electronic tag is attached to the secondary wiring terminals with silicone.

10. The method for manufacturing a current-voltage Y-type combined transformer according to claim 1, characterized in that, The current ratio is permanently marked on the surface of the main insulator by laser etching.

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