Metal shell encapsulated epoxy resin insulation current transformer

Abstract

The utility model relates to the technical field of transformers, in particular to a current transformer which comprises a coil and an epoxy resin layer wrapping the coil, and the epoxy resin layer is provided with a through hole which penetrates through the center of the coil and is used for a circuit to be tested to pass through; the outer side of the epoxy resin layer is encapsulated with a metal shell; the metal shell is provided with two openings corresponding to the through holes; the metal shell is at least provided with a semi-conductive adhesive tape shielding layer and a stainless steel layer arranged outside the semi-conductive adhesive tape shielding layer; the semi-conductive adhesive tape shielding layer in the metal shell is used for shielding a current magnetic field in an adjacent-phase line, the precision of the circuit inductor is improved, and the durability of the current transformer is also improved through the stainless steel layer.

Description

Technical Field

[0001] The present application relates to the technical field of transformers, and in particular to a current transformer. Background Art

[0002] A current transformer is a sensor used to measure current. It measures the magnitude of current by inducing the magnetic field generated by the current. It is usually used to monitor current changes in power distribution systems.

[0003] However, in power stations, distribution systems, large machinery factories and other places, the current in the lines is relatively large and the spacing is small. The current magnetic field in adjacent phase lines can easily affect the current transformer and affect the measurement accuracy of the current transformer. In addition, the environmental conditions in these places are harsh, requiring the current transformer to have higher durability and stability. Utility Model Content

[0004] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract of the specification and the name of the utility model of this application to avoid blurring the purpose of this section, the abstract of the specification and the name of the utility model, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0005] In view of the above problems and / or the problems existing in the prior art, the present utility model is proposed.

[0006] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0007] Metal shell encapsulated epoxy resin insulated current transformer, characterized by:

[0008] It comprises a coil and an epoxy resin layer wrapping the coil, wherein the epoxy resin layer is provided with a through hole passing through the center of the coil for passing a circuit to be tested;

[0009] The epoxy resin layer is encapsulated with a metal shell outside;

[0010] The metal shell is provided with two openings corresponding to the through holes;

[0011] The metal shell has at least one semi-conductive tape shielding layer and a stainless steel layer arranged outside the semi-conductive tape shielding layer; firstly, the utility model optimizes the structure of the metal shell encapsulating the epoxy resin insulated current transformer. After the optimization, the metal shell is encapsulated in the epoxy resin layer of the current transformer, and the semi-conductive tape shielding layer on the metal shell is used to shield the current magnetic field in the adjacent phase line, thereby increasing the accuracy of the circuit sensor and the durability of the current transformer. Secondly, the metal shell increases the durability and stability of the current transformer. Finally, the metal shell is provided with two openings corresponding to the through hole to prevent the metal shell from affecting the coil measurement.

[0012] Preferably, a mounting seat is provided on the lower side of the metal shell, and the mounting seat is provided with a grounding terminal connected to the stainless steel layer; the coil is provided with two wiring terminals, one of which is connected to the stainless steel layer of the metal shell; after optimization, a grounding terminal is provided on the metal shell, and the grounding terminal is connected to the stainless steel layer, so that the metal shell can be grounded to ensure safety and reduce electromagnetic interference.

[0013] Preferably, the outer layer of the epoxy resin layer is made of a material layer of epoxy resin mixed with soft magnetic powder, called a soft magnetic epoxy resin mixed layer, and the soft magnetic epoxy resin mixed layer is compounded on the outside of the epoxy resin layer; the utility model optimizes the structure of the epoxy resin layer, and after the optimization, the soft magnetic epoxy resin mixed layer is used to reduce the influence of the external magnetic field on the coil.

[0014] Preferably, the material of the metal shell is 304 stainless steel; the utility model optimizes the structure of the metal shell, and after the optimization, the 304 stainless steel material of the metal shell has good corrosion resistance and heat resistance.

[0015] Preferably, the coil is also provided with a protection box for insulation protection, the protection box is connected to the side of the metal shell, and the two wiring terminals are fixed in the protection box; the wiring terminals are arranged in the protection box to prevent the wiring terminals from being short-circuited through the metal shell due to dust and humid environment, thereby affecting the detection data of the test instrument.

[0016] Preferably, the protection box is provided with two rubber sleeves, the rubber sleeves are provided on the wires of the coil and against the sides of the epoxy resin layer, and the joints between the rubber sleeves and the epoxy resin layer are sealed with hot melt adhesive; the utility model optimizes the protection box, and after the optimization, the wires of the coil outside the epoxy resin layer are wrapped with rubber sleeves to prevent them from being short-circuited with the metal shell due to dust or humid environment, and the rubber sleeves and the epoxy resin layer are sealed with hot melt adhesive to ensure that the wires of the coil are completely protected.

[0017] Preferably, the protection box is provided with a mounting groove for mounting the wiring terminal, the rubber sleeve is installed at the bottom of the wiring terminal, and the protection box is also provided with a wire connecting the wiring terminal to the metal shell; the utility model optimizes the protection box, and after the optimization, the wiring terminal is installed more stably in the protection box, and the connection and grounding of the wiring terminal to the metal shell are more convenient.

[0018] Preferably, the protection box is also provided with a flip cover, and the flip cover is provided with a sealing ring that cooperates with the inner side of the protection box; the utility model optimizes the structure of the protection box. After the optimization, the sealing ring is used to ensure the sealing of the connection between the protection box and the flip cover, thereby improving the stability of the current transformer.

[0019] Preferably, the metal shell includes two left and right encapsulating shells, the upper sides of the two encapsulating shells are connected by threads, and the lower sides of the two encapsulating shells are rotatably matched with the mounting seat. The utility model optimizes the structure of the metal shell. After the optimization, the left and right encapsulating shells encapsulate the epoxy resin layer and then fasten it with bolts and nuts, making the metal encapsulating shell more convenient to install, and the internal coil and epoxy resin layer are removable, making the replacement of the current transformer more convenient.

[0020] Preferably, a mounting hole is provided at the bottom of the mounting base; the utility model optimizes the structure of the metal shell. After the optimization, the encapsulation shell is tightened with a tightening bolt to enhance the stability of the current transformer structure. The current transformer is connected to the distribution cabinet or other structures with bolts through the mounting hole at the bottom of the mounting base, so that the current transformer can be installed conveniently and stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0022] Figure 1 A schematic diagram of the overall structure of a metal shell encapsulated epoxy resin insulated current transformer according to an embodiment of the utility model;

[0023] Figure 2 A schematic diagram of the structure of a protection box in a metal shell-encapsulated epoxy resin insulated current transformer according to an embodiment of the utility model;

[0024] Figure 3 A schematic diagram of the explosion structure in a metal shell encapsulated epoxy resin insulated current transformer according to an embodiment of the utility model;

[0025] Figure 4The present invention is a schematic diagram of the structural components of a metal shell in a metal shell-encapsulated epoxy resin insulated current transformer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the present invention more understandable, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0029] Secondly, the "one embodiment" or "embodiment" referred to herein refers to a specific feature, structure or characteristic that can be included in at least one implementation of the utility model. The "in one embodiment" that appears in different places in this specification does not refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0030] Example 1

[0031] Reference Figure 1 to Figure 3 , this embodiment provides a metal shell encapsulated epoxy resin insulated current transformer including.

[0032] The invention comprises a coil 101 and an epoxy resin layer 102 wrapping the coil 101, wherein the epoxy resin layer 102 is provided with a through hole passing through the center of the coil 101 for passing the circuit to be tested; a metal shell 103 is provided on the outside of the epoxy resin layer 102; the metal shell 103 is provided with two openings corresponding to the through hole; the metal shell 103 has at least one semi-conductive tape shielding layer and a stainless steel layer arranged outside the semi-conductive tape shielding layer; the coil 101 is an enameled round copper wire winding, and the epoxy resin is cast and formed into the epoxy resin layer 102 to wrap the coil 101, leaving only some of the ends for installing the terminal 101a, and the wire is connected to the epoxy resin layer 102. The epoxy resin layer of the current transformer encapsulates the metal shell, and the semi-conductive tape shielding layer on the metal shell is used to shield the current magnetic field in the adjacent phase line, thereby increasing the accuracy of the circuit sensor and the durability of the current transformer. Secondly, the metal shell increases the durability and stability of the current transformer. Finally, the metal shell is provided with two openings corresponding to the through holes to prevent the metal shell from affecting the coil measurement. The first and tail end wires of the coil 101 are connected to the terminal 101a. The semi-conductive tape shielding layer is a semiconductor self-adhesive tape of model BDD-50, which is suitable for electric field shielding below 500KV and working temperature within 90 degrees.

[0033] A mounting base 103a is provided on the lower side of the metal shell 103, and the mounting base 103a is provided with a grounding terminal connected to the stainless steel layer; the coil is provided with two connecting terminals 101a, one of which is connected to the stainless steel layer of the metal shell 103; a grounding terminal is provided on the metal shell, and the grounding terminal is connected to the stainless steel layer, so that the metal shell and the connecting terminal can be grounded to ensure the safety of the overall equipment and reduce electromagnetic interference.

[0034] The outer layer of the epoxy resin layer 102 is made of epoxy resin mixed with soft magnetic powder, called a soft magnetic epoxy resin mixed layer, which is compounded on the outside of the epoxy resin layer 102; the material of the soft magnetic powder is made of ferrite material and has good electromagnetic shielding performance.

[0035] The material of the metal shell 103 is 304 stainless steel; the 304 stainless steel material of the metal shell has good corrosion resistance and heat resistance.

[0036] The coil 101 is also provided with a protection box 101b for insulation protection. The protection box 101b is connected to the side of the metal shell 103. Two wiring terminals 101a are fixed in the protection box 101b. The wiring terminals 101a are installed in the protection box 101b. The protection box 101b is made of an insulating plastic material. The wiring terminals 101a are protected by the protection box 101b to increase the dust and humid environment resistance of the current transformer and increase its stability. The wiring terminals 101a are installed in the protection box with screws. It is more convenient to connect the wiring terminals 101a to the metal shell 103 with a wire for grounding.

[0037] The protection box 101b is equipped with two rubber sleeves 101b-1. The rubber sleeve 101b-1 is sleeved on the wire of the coil 101 and rests against the side of the epoxy resin layer 102. The joint between the rubber sleeve 101b-1 and the epoxy resin layer 102 is sealed with hot melt adhesive. The rubber sleeve 101b-1 is used to protect the exposed wires between the epoxy resin layer 102 and the protection box 101b to prevent the wires from being short-circuited with the metal shell due to dust or humid environment. The rubber sleeve 101b-1 and the epoxy resin layer 102 are sealed with hot melt adhesive to ensure that the wires of the coil are completely protected and the rubber sleeve 101b-1 will not fall off.

[0038] The protection box 101b is provided with an installation groove for installing the wiring terminal 101a, the rubber sleeve 101b - 1 is installed at the bottom of the wiring terminal 101a, and the protection box 101b is also provided with a wire connecting the wiring terminal 101a and the metal shell 103.

[0039] The protection box 101b is also provided with a flip cover 103b-2, and a sealing ring is provided on the flip cover 103b-2 to cooperate with the inner side of the protection box 101b; the sealing ring is used to ensure the sealing of the connection between the protection box 101b and the flip cover, thereby improving the stability of the current transformer.

[0040] When in use, the coil 101 is fixed in the mold, and then epoxy resin is cast. When the epoxy resin is about to solidify, soft magnetic powder is wrapped on the outer layer of the epoxy resin and mixed with the epoxy resin to solidify into a soft magnetic epoxy resin mixed layer. The soft magnetic epoxy resin mixed layer is wrapped with a semi-conductive tape shielding layer and then the tape at the through hole is removed. Then, the metal shell 103 is encapsulated on the outside of the epoxy resin layer 102, and then the protection box 101b is connected to the metal shell 103 with screws, and two rubber sleeves 101b-1 are put on the wires at the ends of the coil 101 and the rubber sleeves 101b-1 are pushed to the bottom , seal the rubber sleeve 101b-1 and the epoxy resin layer 102 with hot melt adhesive, connect the terminal 101a to the wires at the head and tail of the coil 101 and fix them in the protection box 101b, and finally connect one of the terminal 101a to the wire in the protection box 101b, and then connect the wire to the metal shell with screws. The metal shell encapsulates the epoxy resin insulated current transformer assembly, and the semi-conductive tape shielding layer and the grounded metal shell 103 can effectively reduce electromagnetic interference. The 304 stainless steel metal shell 103 has higher durability and stability.

[0041] Example 2

[0042] Reference Figure 3 and Figure 4 , which is the second embodiment of the utility model, and this embodiment is based on the previous embodiment.

[0043] The metal shell 103 includes two left and right encapsulation shells 103b, the upper sides of the two encapsulation shells 103b are connected by threads, and the lower sides of the two encapsulation shells 103b are rotatably matched with the mounting seat 103a; the bottom of the encapsulation shell 103b is wrapped around a metal cylinder, and the cylinder is welded in the metal shell 103, so that the encapsulation shell 103b can rotate around the metal cylinder.

[0044] The mounting base 103a also includes a cylinder parallel to the rotation axis of the encapsulation shell 103b, and a tightening bolt is provided on the cylinder to tighten the encapsulation shell 103b. A mounting hole is provided at the bottom of the mounting base 103a; the encapsulation shell 103b is tightened by the tightening bolt to enhance the stability of the current transformer structure. The current transformer is connected to the distribution cabinet or other structures with bolts through the mounting hole at the bottom of the mounting base, so that the current transformer can be installed conveniently and stably.

[0045] When in use, the current transformer is installed to a suitable position of the distribution cabinet through the mounting hole on the metal shell 103, the epoxy resin layer 102 is encapsulated by the left and right encapsulation shells 103b, the two encapsulation shells 103b are tightened from the top with bolts, and then the encapsulation shells 103b are tightened from the bottom with tightening bolts, the current transformer is grounded through the grounding terminal, the high-voltage line passes through the middle through hole of the epoxy resin layer 102, and then a grounding terminal 101a of the current transformer is connected to the current output port of the circuit measuring device, and the ungrounded grounding terminal 101a is connected to the current input port of the circuit measuring device; if the current transformer fails, the power supply is disconnected and the power supply wire is pulled out, the locking bolts on the encapsulation shell 103b can be loosened, and then the tightening bolts can be loosened, all the wires on the terminal block can be disconnected, the epoxy resin layer 102 wrapped around the coil 101 can be taken out, and a new epoxy resin layer 102 wrapped around the coil 101 can be replaced and re-wrapped, which can save materials and be economical.

[0046] Importantly, it should be noted that the construction and arrangement of the present application shown in a number of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible, for example, the size, scale, structure, shape and proportion of various elements, and parameter values ​​such as temperature, pressure, etc., mounting arrangements, use of materials, color, directional changes, etc., without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present utility model. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of the execution function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present utility model, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to several modifications still falling within the scope of the appended claims.

[0047] Additionally, in order to provide a concise description of the exemplary embodiments, all features of the actual embodiments may not be described, ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those features that are not relevant to implementing the invention.

[0048] It should be understood that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but for those of ordinary skill having the benefit of this disclosure, the development effort will be a routine task of design, fabrication, and production without undue experimentation.

[0049] It should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. Metal shell encapsulated epoxy resin insulated current transformer, characterized by: It comprises a coil (101) and an epoxy resin layer (102) wrapping the coil (101), wherein the epoxy resin layer (102) is provided with a through hole passing through the center of the coil (101) for passing a circuit to be tested; The epoxy resin layer (102) is encapsulated with a metal shell (103) outside; The metal shell (103) is provided with two openings corresponding to the through holes; The metal shell (103) has at least one semi-conductive tape shielding layer and a stainless steel layer arranged outside the semi-conductive tape shielding layer.

2. The metal shell encapsulated epoxy resin insulated current transformer according to claim 1, characterized in that: A mounting seat (103a) is provided on the lower side of the metal shell (103), and the mounting seat (103a) is provided with a grounding terminal that is conductively connected to the stainless steel layer; The coil is provided with two connection terminals (101a), one of which is connected to the stainless steel layer of the metal shell (103).

3. The metal shell encapsulated epoxy resin insulated current transformer according to claim 2, characterized in that: The outer layer of the epoxy resin layer (102) is a material layer of epoxy resin mixed with soft magnetic powder, called a soft magnetic epoxy resin mixed layer, and the soft magnetic epoxy resin mixed layer is compounded on the outer side of the epoxy resin layer (102).

4. The metal shell encapsulated epoxy resin insulated current transformer according to claim 3, characterized in that: The material of the metal shell (103) is 304 stainless steel.

5. The metal shell encapsulated epoxy resin insulated current transformer according to claim 4, characterized in that: The coil (101) is also provided with a protection box (101b) for insulation protection. The protection box (101b) is connected to the side of the metal shell (103), and the two connection terminals (101a) are fixed in the protection box (101b).

6. The metal shell encapsulated epoxy resin insulated current transformer according to claim 5, characterized in that: The protection box (101b) is provided with two rubber sleeves (101b-1), the rubber sleeves (101b-1) are sleeved on the wires of the coil (101) and pressed against the side of the epoxy resin layer (102), and the rubber sleeves (101b-1) and the epoxy resin layer (102) are sealed at the joints with hot melt adhesive.

7. The metal shell encapsulated epoxy resin insulated current transformer according to claim 6, characterized in that: The protection box (101b) is provided with a mounting groove for mounting the wiring terminal (101a), the rubber sleeve (101b-1) is mounted on the bottom of the wiring terminal (101a), and the protection box (101b) is also provided with a wire for connecting the wiring terminal (101a) and the metal housing (103).

8. The metal shell encapsulated epoxy resin insulated current transformer according to claim 7, characterized in that: The protection box (101b) is further provided with a flip cover (103b-2), and the flip cover (103b-2) is provided with a sealing ring that cooperates with the inner side of the protection box (101b).

9. The metal shell encapsulated epoxy resin insulated current transformer according to claim 8, characterized in that: The metal shell (103) comprises two left and right encapsulation shells (103b), the upper sides of the two encapsulation shells (103b) are connected by threads, and the lower sides of the two encapsulation shells (103b) are rotatably matched with the mounting seat (103a).

10. The metal shell encapsulated epoxy resin insulated current transformer according to claim 9, characterized in that: The mounting seat (103a) further comprises a cylinder parallel to the rotation axis of the encapsulation shell (103b), a clamping bolt for clamping the encapsulation shell (103b) is arranged on the cylinder, and a mounting hole is arranged at the bottom of the mounting seat (103a).

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