Current and voltage combined transformer

Abstract

The utility model relates to a current and voltage combined type mutual inductor which comprises a shell, a current mutual inductance unit and a voltage mutual inductance unit, wherein the current mutual inductance unit and the voltage mutual inductance unit are integrated in the shell. A central channel for a primary side bus of the current mutual inductance unit to pass through is arranged on the shell in a penetrating manner, and the shell is provided with a first assembly gap for introducing a primary side bus of the voltage mutual inductance unit; and the shell is provided with a second assembly gap for a wire harness integrated by the secondary side wires of the current mutual inductance unit and the voltage mutual inductance unit to pass through. According to the integrated combined type mutual inductor, the voltage mutual inductance unit and the current mutual inductance unit are integrated in the same shell, so that the size of the integrated combined type mutual inductor is only slightly larger than that of a single current transformer or a single current transformer, and miniaturization is achieved. Moreover, the current secondary side wire of the current mutual inductance unit and the voltage secondary side wire of the voltage mutual inductance unit are integrated in the same wire harness and are led out through the second assembly gap, so that field wiring is more standard and easier.

Description

Technical Field

[0001] This utility model relates to the field of instrument transformer technology, and in particular to a current-voltage combined instrument transformer. Background Technology

[0002] In the field of industrial instrumentation protection, especially in relay protection applications, the detection of current and voltage is a crucial step. Traditional solutions employ separate current transformers (CTs) and voltage transformers (PTs) to monitor current and voltage.

[0003] In practical use, this independent setup has revealed several drawbacks. First, because a current transformer and a voltage transformer need to be installed separately, each occupying a certain amount of space, the overall footprint is quite large. In space-constrained locations, such as inside a distribution cabinet, this wastes space resources and limits the rational layout of other equipment or components. Furthermore, since both operate independently, the wiring on-site becomes extremely messy. The numerous intertwined wires not only hinder wiring organization and maintenance but also easily lead to wiring errors or potential malfunctions, indicating a need for improvement. Utility Model Content

[0004] In order to overcome at least one of the defects of the prior art, according to one aspect of the present invention, a current-voltage combined transformer is provided, including a housing and a current transformer unit and a voltage transformer unit integrated within the housing.

[0005] The housing has a central channel through which the primary busbar of the current transformer unit passes and has one through-turn, a first assembly notch for the primary busbar of the voltage transformer unit to be introduced, and a second assembly notch for the wire harness integrated by the secondary conductors of both the current transformer unit and the voltage transformer unit to pass through.

[0006] In one embodiment of this application, the voltage transformer unit includes a voltage transformer coil and a PCB board integrated with the voltage transformer coil;

[0007] The PCB board has a primary side access terminal that is connected to the primary winding of the voltage transformer coil. The primary side access terminal is located at the first assembly notch of the housing and is used to connect the primary side bus of the voltage transformer unit.

[0008] In one embodiment of this application, the housing has a slot for attaching a PCB board.

[0009] In one embodiment of this application, the secondary conductors of the current transformer unit and the voltage transformer unit are distinguished by different colors.

[0010] In one embodiment of this application, the housing includes a cover and a bottom shell that are assembled together. A first supporting flange protrudes from the inner wall of the bottom shell, and the cover, the first supporting flange, and the bottom shell pass through each other to form a central channel.

[0011] The current transformer unit includes a current transformer coil, which is sleeved on the circumferential outer side of the first support flange, and the voltage transformer coil of the voltage transformer unit is located above or below the current transformer coil.

[0012] In one embodiment of this application, the first assembly notch is located above the second assembly notch, and the slot of the housing is located between the first assembly notch and the second assembly notch.

[0013] In one embodiment of this application, the PCB board is fixed with a protective shell, and the protective shell is disposed inside the housing;

[0014] The protective shell is provided with a second support flange, and the voltage inductance coil of the voltage inductance unit is sleeved on the circumferential outer side of the second support flange.

[0015] In one embodiment of this application, the portion of the housing where the current transformer unit is located is the first assembly portion, and the portion of the housing where the voltage transformer unit is located is the second assembly portion. The width of the first assembly portion is greater than the width of the second assembly portion, so that a reserved space is left at the first assembly portion for setting the first assembly notch.

[0016] In one embodiment of this application, the current transformer unit is a three-phase current transformer unit and specifically includes three current transformer coils, with three coils correspondingly arranged in the central channel of the housing;

[0017] The voltage inductance unit is a three-phase current inductance unit and specifically includes three voltage inductance coils.

[0018] In one embodiment of this application, the three-phase current transformer unit and the three-phase voltage transformer unit share a common neutral line.

[0019] In summary, the current-voltage combined transformer provided by this utility model has the following technical effects:

[0020] In this application, by integrating the voltage transformer unit and the current transformer unit into the same housing, the overall combined transformer is only slightly larger than a standalone current transformer, achieving miniaturization. Furthermore, the current secondary side conductors of the current transformer unit and the voltage secondary side conductors of the voltage transformer unit are integrated into a single wiring harness and led out through a second mounting notch. This makes field wiring more standardized and easier, avoiding the messy field wiring caused by independent wiring of multiple devices in traditional methods. It facilitates later maintenance and repair, reduces the risk of failure due to messy wiring, and also improves the overall aesthetics. Attached Figure Description

[0021] Figure 1 This is a front view of the current-voltage combined transformer according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the housing of the current-voltage combined transformer according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the bottom shell of the housing of the current-voltage combined transformer according to an embodiment of the present invention;

[0024] Figure 4 This is a cross-sectional view of the internal structure of the current-voltage combined transformer according to an embodiment of the present invention;

[0025] Attached Figures: 1-Housing, 11-Central Channel, 12-First Assembly Notch, 13-Second Assembly Notch, 14-Slot, 15-Cover, 16-Bottom Shell, 17-First Support Flange, 21-Current Inductor, 31-Voltage Inductor, 32-PCB Board, 33-Primary Side Access Terminal, 34-Protective Shell, 35-Second Support Flange. Detailed Implementation

[0026] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0027] In the description of this utility model, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and 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. Therefore, they should not be construed as limitations on this utility model.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0029] This application discloses a current transformer, specifically a current-voltage combined current transformer. Specifically, this application combines a previously separate current transformer and a voltage transformer, reducing product size, facilitating installation, and saving cabinet space.

[0030] The following is in conjunction with the appendix Figures 1-4 This paper will describe in detail the technical solution of the current-voltage combined transformer of this application.

[0031] Specifically, this current-voltage combined transformer includes a housing 1 and a current transformer unit and a voltage transformer unit integrated within the housing 1.

[0032] The housing 1 has a central channel 11 through which the primary busbar of the current transformer unit passes and has one through-turn, and a first assembly notch 12 on the housing 1 for the introduction of the primary busbar of the voltage transformer unit, and a second assembly notch 13 on the housing 1 for the wire harness integrated by the secondary conductors of both the current transformer unit and the voltage transformer unit to pass through.

[0033] Traditionally, current transformers and voltage transformers are manufactured and used separately, each with its own independent casing, occupying a large physical space. Furthermore, the presence of multiple independent devices leads to messy wiring in the field, hindering later maintenance and repair, and increasing the risk of line faults.

[0034] In this application, by integrating the voltage and current transformer units into the same housing 1, the overall combined transformer is only slightly larger than a standalone current transformer, achieving miniaturization. Furthermore, compared to traditional separate manufacturing methods, the combined transformer shares a single housing, reducing the materials required for manufacturing, such as eliminating the housing of one transformer and some connecting components, thereby lowering raw material costs. It also reduces assembly steps, lowering labor and equipment usage costs, thus reducing the overall product cost. Moreover, this compact design saves cabinet space, facilitating layout within limited installation space and improving space utilization.

[0035] Furthermore, since traditional voltage transformers require separate fixed installation, in this combined transformer, the voltage transformer unit and the current transformer unit are integrated into the same housing 1. Once the primary current bus of the current transformer unit is installed, the installation problem of the voltage transformer unit is solved at the same time, greatly simplifying the installation process and improving installation efficiency.

[0036] More importantly, the current secondary side conductors of the current transformer unit and the voltage secondary side conductors of the voltage transformer unit are integrated into a single wire harness and led out through the second assembly notch 13. This makes the on-site wiring more standardized and easier, avoiding the messy on-site wiring caused by the independent wiring of multiple devices in the traditional method. It facilitates later maintenance and repair, reduces the risk of failure caused by messy wiring, and also improves the overall aesthetics.

[0037] Furthermore, this combined instrument transformer integrates current and voltage measurement functions within a single device, enabling simultaneous implementation of two protection functions. This provides a more convenient and efficient solution for applications such as relay protection, meeting the need for simultaneous current and voltage detection on the same line. Its enhanced integration and unification of functions improves system reliability and stability. Therefore, this integrated design allows primary-side current and voltage measurements to be completed simultaneously within a single device, avoiding the problem of distributing multiple devices.

[0038] Specifically, the voltage transformer unit includes a voltage transformer coil 31 and a PCB board 32 integrated with the voltage transformer coil 31; the PCB board 32 has a primary side access terminal 33 connected to the primary winding wound on the voltage transformer coil 31, and the primary side access terminal 33 is located at the first assembly notch 12 of the housing 1 for connecting the primary side bus of the voltage transformer unit.

[0039] Because traditional voltage transformers use a distributed wiring connection method, the connection of their primary bus is not convenient enough. It requires a relatively complex wiring and connection method to introduce external voltage into the coil of the voltage transformer, which increases the difficulty of installation and maintenance.

[0040] To address this, this application provides a primary-side access terminal 33 on the PCB board, connected to the primary winding of the voltage transformer coil 31. This primary-side access terminal 33 allows for easy connection to the primary-side busbar of an external voltage transformer unit. This design centralizes complex wiring connections on the PCB board, simplifying and accelerating the connection of external voltage input lines, reducing the operational complexity for on-site installers, and improving connection reliability. Furthermore, integrating the voltage transformer coil 31 with the PCB board results in a more compact and integrated overall structure for the voltage transformer. This integrated design facilitates better layout of the current transformer within the housing 1 of the combined transformer, providing a solid foundation for the compact integration of the current transformer and voltage transformer, thereby reducing the overall size of the combined transformer.

[0041] Specifically, the housing 1 has a slot 14 for the PCB board 32 to be snapped into. In actual assembly, other fixing measures (such as glue, cable ties or other auxiliary fixing devices) are usually used to fix the PCB board in the housing 1. This not only increases the assembly process and time, but may also introduce other impurities (such as glue residue), affecting the quality and reliability of the product.

[0042] To address this, this application incorporates a slot 14 within the housing 1 for securing the PCB board. This slot precisely fixes the PCB board in place, preventing displacement or movement within the housing 1 and ensuring the stability of the voltage transformer unit under various operating conditions (including transportation, installation, and normal operation). This helps protect the components on the PCB board, preventing damage due to mechanical stress and extending the product's lifespan. Furthermore, the slot 14 simplifies the PCB board installation process. Assemblers simply insert the PCB board into the slot 14 to complete the installation, eliminating the need for additional fixing devices and significantly reducing assembly time and improving production efficiency. Simultaneously, it reduces potential quality issues arising from the use of auxiliary fixing devices, ensuring product quality and reliability.

[0043] Specifically, the secondary conductors of the current transformer and the voltage transformer are distinguished by different colors. In traditional transformer designs, if the secondary conductors of the current transformer and the voltage transformer are not clearly distinguished, field technicians can easily confuse the two types of conductors during wiring, connection, and maintenance. This can lead to incorrect wiring, affecting the normal operation of the entire system and even causing safety hazards, such as causing measuring equipment to receive incorrect signals or damaging the equipment.

[0044] Although the secondary side conductors of both the current transformer and the voltage transformer are integrated into a single wiring harness in this application, in actual use, it is still necessary to distinguish between the secondary side conductors of the current transformer and the voltage transformer. Therefore, by using different colors to differentiate the secondary side conductors of the current transformer and the voltage transformer, on-site technicians can quickly and accurately identify their respective functional conductors among numerous wires. This greatly facilitates wiring, connection, and maintenance work, reduces the risk of wiring errors due to misoperation, and improves the accuracy and reliability of the work.

[0045] For example, yellow-sheathed wires are used for the secondary side conductors of current transformers, while red-sheathed wires are used for the secondary side conductors of voltage transformers. This allows operators to easily identify the different functions of the wires by observing the color of the sheath when integrating them into a single wiring harness.

[0046] Specifically, housing 1 includes a cover 15 and a bottom shell 16 that are assembled together. A first supporting flange 17 protrudes from the inner wall of the bottom shell 16. The cover 15, the first supporting flange 17, and the bottom shell 16 all pass through to form a central channel 11. The current transformer unit includes a current transformer coil 21, which is sleeved on the circumferential outer side of the first supporting flange 17. The voltage transformer coil 31 of the voltage transformer unit is located above or below the current transformer coil 21. In designing the structure of housing 1, which integrates the current transformer and voltage transformer, without proper internal support and layout planning, the installation of the transformers within housing 1 may be unstable. Furthermore, determining the relative positions of the voltage transformer coil 31 and the current transformer coil 21 without specific design considerations makes it difficult to achieve a compact and reasonable layout. This may result in mutual interference between the two, or excessive space being reserved to avoid interference, leading to an excessively large overall size of housing 1 that fails to meet miniaturization requirements.

[0047] To address this, the first support flange 17, protruding from the inner wall of the bottom shell 16, provides stable circumferential outer support for the current transformer coil 21. The current transformer coil 21 is fitted onto the first support flange 17, effectively preventing it from shaking or shifting within the shell 1, ensuring the stability of the current transformer during operation, and reducing the adverse effects on its performance caused by mechanical vibration or external impact. Furthermore, this stable structural design also helps protect internal wiring connections, reducing problems such as wire pulling and wear caused by coil movement, thus improving product reliability and service life.

[0048] Meanwhile, by rationally arranging the voltage transformer coil 31 above or below the current transformer coil 21, and constructing the central channel 11 using the first supporting flange 17, a compact and efficient spatial layout is achieved. The layered arrangement of the voltage transformer coil 31 and the current transformer coil 21 in the vertical direction makes full use of the space inside the housing 1 and avoids mutual space occupation in the horizontal direction, thus effectively controlling the overall volume of the housing 1. Compared with the traditional separate transformer design, it better meets the requirements of miniaturization, saves installation space, and is beneficial for application in equipment or places with high space requirements.

[0049] In the illustrated embodiment, the first support flange 17 and the first assembly notch 12 may be specifically provided in the bottom shell 16.

[0050] In the illustrated embodiment, the voltage inductor 31 is positioned above the current inductor 21. Of course, in other embodiments, the positions of the voltage inductor 31 and the current inductor 21 can be set according to actual conditions.

[0051] Specifically, the first assembly notch 12 is located above the second assembly notch 13, and the slot 14 is located between the first assembly notch 12 and the second assembly notch 13. If the positions of the assembly notches and slots 14 are arbitrarily set when designing the layout of the transformer housing 1 and its internal components, it may lead to mutual interference between the wiring connections of the voltage transformer unit (through the first assembly notch 12), the lead-out of the current and voltage transformer secondary side wires (through the second assembly notch 13), and the installation of the PCB board (through the slot 14). For example, the wiring may become tangled or jammed when passing through different notches, affecting the smooth progress of assembly, increasing assembly time and difficulty, and potentially causing wear, short circuits, and other problems during later use due to unreasonable wiring layout.

[0052] In contrast, this application's layout, with the first assembly notch 12 positioned above the second assembly notch 13 and the slot 14 located between them, allows for the orderly connection of the primary busbar, the lead-out of the secondary conductors, and the installation of the PCB board of the voltage transformer unit. During assembly, operators can install and connect components sequentially from top to bottom (or vice versa), reducing the possibility of wire crossings and tangles and improving assembly efficiency. Furthermore, this layout facilitates full utilization of the internal space of the housing 1, achieving a compact design. Each component and circuit can be arranged orderly within its respective spatial area, avoiding space waste and chaos, effectively controlling the overall size of the combined transformer, making it more suitable for installation and use in confined spaces such as distribution cabinets.

[0053] Specifically, a protective shell 34 is fixed to the PCB board 32 and is disposed inside the housing 1. A second support flange 35 is provided inside the protective shell 34, and the voltage transformer coil 31 of the voltage transformer unit is sleeved on the circumferential outer side of the second support flange 35. In actual assembly, it was found that without a suitable positioning structure, the positional stability of the voltage transformer coil 31 within the housing 1 is poor. It may be displaced due to vibration or other mechanical interference, changing its relative positional relationship with other components (such as the current transformer coil 21), thereby disrupting the stability of the electromagnetic coupling and degrading the overall performance of the transformer.

[0054] To address this, a protective housing 34 is provided in this application. The protective housing 34 provides a physical barrier for the voltage inductor coil 31, effectively blocking external dust, moisture, and a certain degree of mechanical impact, protecting the coil from damage, ensuring it maintains normal electromagnetic performance under various complex environments, stably performing voltage measurements, and extending the service life of the voltage inductor unit. Simultaneously, the second support flange 35 inside the protective housing 34 provides precise positioning and stable support for the voltage inductor coil 31. The voltage inductor coil is sleeved around the second support flange 35, ensuring its fixed position within the housing 1 and preventing displacement. This guarantees the stability of its relative positional relationship with other components such as the current inductor coil 21, which helps maintain good electromagnetic coupling and improves the accuracy and consistency of the transformer measurements.

[0055] Furthermore, the protective housing 34 tightly integrates the voltage transformer coil 31 and the PCB board, forming a relatively stable overall structure. When faced with temperature changes, mechanical vibrations, etc., the protective housing 34 can act as a buffer and constraint, reducing the risk of loosening or damage to the connection caused by thermal expansion and contraction of materials or external forces, enhancing the reliability of the connection between the two, and ensuring the long-term stable operation of the voltage transformer unit.

[0056] Specifically, the current transformer unit is a three-phase current transformer unit and specifically includes three current transformer coils 21, with three correspondingly arranged in the central channel 11 of the housing 1; the voltage transformer unit is a three-phase current transformer unit and specifically includes three voltage transformer coils 31.

[0057] In traditional designs, three-phase current transformers and three-phase voltage transformers are usually installed separately, each with its own housing and structural frame. When integrating them, how to rationally arrange the spatial positions of the three current transformer coils 21 and the three voltage transformer coils 31 becomes a major challenge. An unreasonable layout will result in an excessively large housing 1, making it impossible to achieve the miniaturization design goal and hindering installation and use in some space-constrained distribution cabinets or electrical equipment compartments.

[0058] In this application, the three-phase current transformer unit and the three-phase voltage transformer unit are integrated into a common housing 1. By cleverly arranging the relative positions of the three current transformer coils 21 and the three voltage transformer coils 31—for example, with the three current transformer coils 21 located above the three voltage transformer coils 31—the overall size of the transformer can be significantly reduced. Compared to traditional separate three-phase transformers, this integrated design is more efficient in space utilization, meeting the needs of more space-constrained applications, such as compact distribution cabinets and prefabricated modules in smart substations. This improves the space utilization rate of the equipment and reduces the overall size and weight of the equipment.

[0059] Furthermore, integrating the three-phase coils together simplifies the overall wiring structure, allows for unified planning of the primary and secondary wiring routes, reduces the total length of the lines and the number of connection points, not only lowers wiring costs and assembly difficulty, but also reduces electromagnetic interference caused by poor or excessively long line connections, improves the electromagnetic compatibility of the transformer, and makes the entire system more stable and reliable.

[0060] For example, in the illustrated embodiment, the primary bus detected by the three-phase current transformer unit will also have three, so one primary bus corresponds to one central channel 11.

[0061] Specifically, the location of the current transformer unit in housing 1 is the first assembly location, and the location of the voltage transformer unit in housing 1 is the second assembly location. The width of the first assembly location is greater than the width of the second assembly location, so as to leave reserved space at the first assembly location for the first assembly notch 12. If the dimensions of each assembly location are not properly planned when designing the internal space layout of the transformer housing 1, it may lead to conflicts between the voltage transformer unit and the current transformer unit during installation.

[0062] To address this, the width of the first assembly section is designed to be greater than the width of the second assembly section, specifically providing adequate space for the first assembly notch 12. This allows the primary side access terminal 33 on the PCB board 32 to be smoothly assembled into the first assembly notch 12 without negatively impacting the installation and layout of the current transformer unit. This differentiated spatial design fully considers the functional requirements and connection characteristics of each component, improves the utilization rate of the internal space of the housing 1, and helps to achieve a compact and efficient layout, making the entire transformer smaller and more suitable for installation and use in space-constrained equipment such as distribution cabinets.

[0063] Specifically, both the three-phase current transformer and the three-phase voltage transformer share a common neutral line. To simplify wiring connections and save space, when routing the secondary side conductors of both transformers using a wiring harness, their neutral lines are combined into one. During harness fabrication, a suitable wiring method is used (e.g., setting a common neutral line connection point on the PCB board, or connecting the neutral lines of both transformers together using dedicated terminals) to achieve this shared neutral line. Furthermore, color coding can be used for differentiation, allowing installation, commissioning, and maintenance personnel to quickly identify the neutral line and other conductors with different functions among numerous wires, improving work efficiency and reducing the probability of errors.

[0064] Furthermore, in some circuits that require both voltage and current signals for power measurement or protection action judgment, a shared neutral line can provide a unified reference point, enabling voltage and current signals to be used in calculations (such as calculating power factor, judging overcurrent and overvoltage conditions) based on the same potential reference, thus reducing errors caused by different reference potentials.

[0065] The technical means disclosed in this utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications are also considered within the scope of protection of this utility model.

Claims

1. A current-voltage combined transformer, characterized by, The shell (1) is provided with a central passage (11) for the primary bus of the current mutual inductance unit to pass through, and the central passage (11) has one turn number, and the shell (1) is provided with a first assembly gap (12) for the primary bus of the voltage mutual inductance unit to be introduced, and the shell (1) is provided with a second assembly gap (13) for the wire harness of the secondary side lead of the current mutual inductance unit and the voltage mutual inductance unit to pass through. The voltage mutual inductance unit comprises a voltage mutual inductance coil (31) and a PCB (32) integrated with the voltage mutual inductance coil (31).

2. A combined current and voltage transformer according to claim 1, characterized in that The PCB (32) is provided with a primary side access terminal (33) connected with the primary winding of the voltage mutual inductance coil (31), and the primary side access terminal (33) is arranged at the first assembly gap (12) of the shell (1) and used for connecting the primary bus of the voltage mutual inductance unit. The shell (1) is provided with a clamping groove (14) for clamping the PCB (32).

3. A combined current and voltage transformer according to claim 2, characterized in that The secondary side lead of the current mutual inductance unit and the voltage mutual inductance unit is distinguished by different colors.

4. The current-voltage combined transformer of claim 1, wherein, The shell (1) comprises a cover (15) and a bottom shell (16) assembled with each other, the inner wall of the bottom shell (16) is protruded to form a first support flange (17), and the cover (15), the first support flange (17) and the bottom shell (16) are penetrated to form the central passage (11).

5. A combined current and voltage transformer according to any one of claims 1 to 4, characterized in that The current mutual inductance unit comprises a current mutual inductance coil (21), the current mutual inductance coil (21) is sleeved on the circumferential outer side of the first support flange (17), and the voltage mutual inductance coil (31) of the voltage mutual inductance unit is located on the upper side or the lower side of the current mutual inductance coil (21). The first assembly gap (12) is located above the second assembly gap (13), and the clamping groove (14) of the shell (1) is located between the first assembly gap (12) and the second assembly gap (13).

6. A combined current and voltage transformer according to claim 5, characterized in that The PCB (32) is fixed with a protective shell (34), and the protective shell (34) is arranged in the shell (1).

7. The current-voltage combined transformer of claim 2, wherein, The protective shell (34) is provided with a second support flange (35), and the voltage mutual inductance coil (31) of the voltage mutual inductance unit is sleeved on the circumferential outer side of the second support flange (35). The part of the shell (1) where the current mutual inductance unit is located is a first assembly part, the part of the shell (1) where the voltage mutual inductance unit is located is a second assembly part, and the width of the first assembly part is greater than the width of the second assembly part, so that a reserved space for arranging the first assembly gap (12) is left in the first assembly part.

8. A combined current and voltage transformer according to any one of claims 1 to 4, characterized in that The current mutual inductance unit is a three-phase current mutual inductance unit and specifically comprises three current mutual inductance coils (21), and the central passage (11) of the shell (1) is correspondingly provided with three central passages.

9. A combined current and voltage transformer according to any one of claims 1 to 4, characterized in that The voltage mutual inductance unit is a three-phase voltage mutual inductance unit and specifically comprises three voltage mutual inductance coils (31). The three-phase current mutual inductance unit and the three-phase voltage mutual inductance unit share a common neutral line.

10. A combined current and voltage transformer according to claim 9, characterized in that ​

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