Vacuum heat conduction potting structure of current transformer and manufacturing process thereof

Abstract

The application discloses a vacuum heat conduction pouring sealing structure of a current transformer and a manufacturing process thereof. The device comprises a shell, a metal pin, a winding and a magnetic core arranged from bottom to top in the shell, an exhaust buffering unit arranged in the shell, a framework arranged in the winding of the exhaust buffering unit, a flow guide member arranged at the bottom of the framework, an exhaust member arranged at the highest position in the shell, and a buffering member arranged in the shell. The device makes the pouring glue flow uniformly from bottom to top by the flow guide member, fills the gap between the winding coils and the joint of the magnetic core, realizes complete exhaust under the vacuum environment by the exhaust member, avoids bubble residues to improve insulation, adds heat conduction fillers to the pouring glue, completely wraps the winding and the magnetic core to form a heat conduction channel, rapidly leads out heat to delay aging, meanwhile, the buffering cavity provides a deformation space for the thermal expansion and cold contraction of the glue, effectively absorbs internal stress and reduces the cracking risk, and meets the demand of users.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum heat conduction potting of current transformers, and particularly relates to a vacuum heat conduction potting structure of a current transformer and a manufacturing process thereof. BACKGROUND

[0002] As a key metering and protection device in a power system, a current transformer essentially belongs to a special transformer. It converts a large current in a high-voltage line into a small current in a low-voltage line according to the principle of electromagnetic induction, and provides a standard signal for power metering instruments, relay protection devices, etc.

[0003] However, the existing current transformer has the following problems during potting. First, the potting glue flows unevenly in the shell during conventional potting, and air bubbles are easily retained at the gap between the winding coil, the joint between the magnetic core and the skeleton, and other parts. These air bubbles will cause the internal insulation performance of the current transformer to continuously decrease, and there is a limitation. Second, the existing potting material is mostly ordinary epoxy resin, which has a generally low thermal conductivity coefficient and cannot effectively conduct heat out, resulting in a continuous increase in internal temperature and a shortened service life of the device. Finally, the thermal expansion coefficients of the existing potting glue and the metal pins, magnetic cores, and other components inside the current transformer are quite different. During temperature cycling caused by load fluctuation of the power system, the shrinkage and expansion of different materials are different, and internal stress is continuously generated inside the potting glue and at the joint between the potting glue and the components. The potting glue is prone to cracking under the long-term effect, and loses the sealing and protection effect on the internal core components, which has a limitation.

[0004] The reason for this problem is that the potting glue in the conventional potting process is mostly injected from a single direction, which cannot uniformly fill the complex gap inside the shell, resulting in difficulty in exhausting gas and forming air bubbles. Second, the existing potting material only focuses on insulation performance and does not optimize the filler ratio for heat conduction requirements. Finally, the potting process lacks targeted vacuum assistance and stress relief design. Conventional atmospheric potting cannot completely exhaust the internal gas, and a special buffer structure is not provided to absorb the internal stress generated by temperature cycling, which ultimately leads to frequent problems of air bubble retention, insufficient heat conduction, and cracking, and has a limitation. SUMMARY

[0005] The present application aims to provide a vacuum heat conduction potting structure of a current transformer and a manufacturing process thereof to solve the problems raised in the background.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a vacuum heat conduction potting structure of a current transformer and a manufacturing process thereof, comprising a shell, a metal pin, a winding, and a magnetic core are arranged in the shell from bottom to top, an exhaust buffer unit is arranged in the shell, and the exhaust buffer unit comprises a flow guide piece, an exhaust piece, and a buffer piece.

[0007] The winding is internally provided with a framework, the flow guide is opened at the bottom of the framework, the flow guide is used to guide the uniform flow of the potting adhesive from bottom to top and completely wrap the winding, the exhaust member is opened at the highest position inside the shell, the exhaust member is used to exhaust the gas inside the shell when the glue is filled, the buffer member is arranged inside the shell, and the buffer member is used to provide a directional deformation space when the potting adhesive expands and contracts, thereby absorbing and releasing internal stress.

[0008] Preferably, the flow guide comprises a main flow groove and a branch flow groove.

[0009] The main flow groove is opened at the bottom of the framework, and the main flow groove is designed in a spiral shape as a whole; the branch flow groove is opened on the framework, the main flow groove is communicated with the branch flow groove, the width of the branch flow groove is smaller than that of the main flow groove, and the branch flow groove is used to transport and fill the gap between each layer of coils.

[0010] Preferably, the flow guide further comprises an annular groove.

[0011] The magnetic core is arranged at the top of the framework, the annular groove is opened at the assembly joint of the magnetic core and the framework, and the annular groove is communicated with the branch flow groove.

[0012] Preferably, the exhaust member comprises an exhaust hole and an exhaust cavity.

[0013] The exhaust hole is opened at the highest position inside the shell, and the exhaust holes are arranged in an equidistant array; the exhaust cavity is fixedly assembled in the inner wall of the shell, the exhaust hole is communicated with the exhaust cavity, and the exhaust cavity is in a tapered structure as a whole from bottom to top.

[0014] Preferably, the exhaust member further comprises an exhaust main channel.

[0015] The exhaust main channel is opened in the interior of the shell, the exhaust main channel is communicated with the exhaust cavity, and the exhaust main channel and the exhaust cavity are at an angle of 45°.

[0016] Preferably, the buffer member comprises a main buffer cavity.

[0017] The main buffer cavity is opened at the bottom of the metal pin, the bottom of the shell is provided with a potting adhesive injection port, and the main buffer cavity is communicated with the potting adhesive injection port and the main flow groove, respectively.

[0018] Preferably, the buffer member further comprises a secondary buffer cavity.

[0019] The secondary buffer cavity is opened at the inner top of the shell, and the main buffer cavity and the secondary buffer cavity are in a hemispherical structure as a whole.

[0020] Preferably, the method comprises the following steps:

[0021] S1, preparation of potting material, preparation of modified epoxy resin composite material;

[0022] S2, processing of internal mechanical mechanism of shell, forming flow guide structure, exhaust structure and buffer structure in the inside of shell;

[0023] S3, vacuum potting process, injecting potting material into the inside of shell under vacuum environment and solidifying;

[0024] S4, product detection and verification, detecting insulation, heat conduction, mechanical and appearance performance of the solidified product.

[0025] Preferably, the preparation of potting material in step S1 includes the following steps:

[0026] S11, batching stage, preparing each component according to the following weight percentage: epoxy resin matrix: 60-70wt%, heat-conducting filler: 25-35wt%, toughening agent: 3-5wt%, curing agent: 2-4wt%;

[0027] S12, preliminary mixing, placing the epoxy resin matrix and heat-conducting filler in a high-speed disperser, stirring at 1500-2000rpm for 30-40 minutes at 60-70°C to ensure sufficient mixing;

[0028] S13, toughening agent addition, adding the toughening agent into the above mixture, reducing the speed to 500-800rpm, stirring for 15-20 minutes to ensure the dispersion of the filler;

[0029] S14, curing agent addition, placing the above mixture into a vacuum defoaming machine, then adding the curing agent, stirring at 300-500rpm at room temperature for 10-15 minutes to ensure no bubbles, and outputting the glue;

[0030] S15, thixotropy detection, sampling detection by rotary viscometer to ensure that the static viscosity of the glue is ≥5000cP and the stirring viscosity is ≤1000cP, and the modified epoxy resin composite material meeting the requirements is filled into a sealed container for standby.

[0031] Preferably, the vacuum potting process in step S3 includes the following steps:

[0032] S31, preheating stage, placing the shell into a heating box and preheating to 60-80°C, heating the potting glue to 50-60°C, reducing the viscosity of the glue to below 1000cP to improve the flowability;

[0033] S32, vacuum degassing, the preheated shell is put into the vacuum chamber, vacuumized to ≤100Pa, and kept for 15-20 minutes, so that air and moisture in the winding gap and the magnetic core gap are completely extracted;

[0034] S33, pressure injection, in the vacuum environment, the potting adhesive is injected from the bottom of the shell through the precise metering pump, the injection pressure is 0.1-0.3MPa, the glue liquid rising speed is 5-10mm / min, and air is discharged from the top exhaust part;

[0035] S34, step curing, a programmed temperature curve is adopted, the glue is preliminarily cured at 60℃ for 2 hours, then the glue is mainly cured at 100℃ for 4 hours, finally the glue is finally solidified at 125℃ for 2 hours.

[0036] Technical effects and advantages of the present application:

[0037] 1. The device guides the potting adhesive to flow uniformly from bottom to top through the spiral main guide groove and branch guide groove, ensures that the glue fills the winding coil gap and the magnetic core joint, and the exhaust hole at the top of the shell, the gradually expanding exhaust cavity and the 45° angle exhaust main channel cooperate to completely discharge the gas in the shell in the vacuum environment, avoid bubble residue, and improve the insulation performance of the equipment.

[0038] 2. The heat-conducting filler is added in the modified epoxy resin composite material to improve the thermal conductivity of the potting material, and the potting adhesive can completely wrap the winding and the magnetic core to form a continuous heat-conducting channel, quickly conduct the internal heat, slow down the aging speed of the parts, and prolong the service life of the equipment.

[0039] 3. The main buffer cavity and the auxiliary buffer cavity provide a directional deformation space for the thermal expansion and cold contraction of the potting adhesive, which can effectively absorb the internal stress caused by thermal expansion and cold contraction in the device, and in addition, the toughness of the glue is improved by adding a toughening agent in the potting material, which further reduces the cracking risk and meets the needs of users. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 It is a schematic diagram of the overall structure of the present application;

[0041] Figure 2 It is a schematic diagram of the shell inside the present application;

[0042] Figure 3 It is a schematic diagram of the exhaust buffer unit of the present application;

[0043] Figure 4 It is a schematic diagram of the branch guide groove of the present application;

[0044] Figure 5 It is a schematic diagram of the manufacturing process flow of the present application;

[0045] Figure 6 This is a schematic diagram of the preparation process of the potting material of the present invention;

[0046] Figure 7 This is a schematic diagram of the vacuum potting process of the present invention.

[0047] In the diagram: 1. Outer shell; 2. Metal pins; 3. Winding; 4. Magnetic core; 5. Frame; 6. Exhaust buffer unit; 61. Flow guide; 611. Main flow channel; 612. Branch flow guide; 613. Annular groove; 62. Exhaust component; 621. Exhaust hole; 622. Exhaust chamber; 623. Main exhaust channel; 63. Buffer component; 631. Main buffer chamber; 632. Secondary buffer chamber. Detailed Implementation

[0048] 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. 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.

[0049] This invention provides, for example Figures 1 to 4 The vacuum thermal encapsulation structure and manufacturing process of a current transformer shown herein include a housing 1, wherein metal pins 2, windings 3 and magnetic cores 4 are arranged from bottom to top inside the housing 1. The housing 1 is characterized by having an exhaust buffer unit 6 inside, which includes a flow guide 61, an exhaust component 62 and a buffer component 63.

[0050] The winding 3 has a frame 5 inside, and a flow guide 61 is opened at the bottom of the frame 5. The flow guide 61 is used to guide the potting compound to flow evenly from bottom to top and completely wrap the winding 3. The vent 62 is opened at the highest point inside the outer shell 1. The vent 62 is used to expel the gas inside the outer shell 1 during the filling of the compound. The buffer 63 is set inside the outer shell 1. The buffer 63 is used to provide directional deformation space for the potting compound when it expands and contracts with heat, thereby absorbing and releasing internal stress.

[0051] The flow guide 61 comprises a main flow guide groove 611 and a branch flow guide groove 612; the main flow guide groove 611 is arranged on the bottom of the framework 5, and the main flow guide groove 611 is designed in a spiral shape as a whole; the branch flow guide groove 612 is arranged on the framework 5, the main flow guide groove 611 is communicated with the branch flow guide groove 612, the width of the branch flow guide groove 612 is smaller than that of the main flow guide groove 611, and the branch flow guide groove 612 is used for conveying and filling the gap between each layer of coils with the colloid. The flow guide 61 further comprises an annular groove 613; the magnetic core 4 is arranged on the top of the framework 5, the annular groove 613 is arranged at the assembly joint of the magnetic core 4 and the framework 5, and the annular groove 613 is communicated with the branch flow guide groove 612. The exhaust member 62 comprises exhaust holes 621 and an exhaust cavity 622; the exhaust holes 621 are arranged at the highest position in the inside of the shell 1, and the exhaust holes 621 are arranged in an equidistant array; the exhaust cavity 622 is fixedly arranged in the inner wall of the shell 1, the exhaust holes 621 are communicated with the exhaust cavity 622, and the exhaust cavity 622 is designed in a taper structure as a whole from bottom to top. The exhaust member 62 further comprises an exhaust main passage 623; the exhaust main passage 623 is arranged in the inside of the shell 1, the exhaust main passage 623 is communicated with the exhaust cavity 622, and the exhaust main passage 623 and the exhaust cavity 622 are arranged at an angle of 45°. The buffer member 63 comprises a main buffer cavity 631; the main buffer cavity 631 is arranged on the bottom of the metal pin 2, the bottom of the shell 1 is provided with a potting glue injection port, and the main buffer cavity 631 is respectively communicated with the potting glue injection port and the main flow guide groove 611. The buffer member 63 further comprises a secondary buffer cavity 632; the secondary buffer cavity 632 is arranged on the inner top of the shell 1, and the main buffer cavity 631 and the secondary buffer cavity 632 are designed in a hemispherical structure as a whole.

[0052] In the embodiment, in the potting process, the spiral main flow guide groove 611 in the flow guide 61 enables the potting glue to be evenly diffused along a spiral path after being injected from the bottom injection port of the shell 1, thereby avoiding local glue accumulation; the branch flow guide groove 612 can accurately convey the glue to the gap of each layer of coils of the winding 3 due to the smaller width than that of the main flow guide groove 611, and the glue can completely wrap the bottom of the magnetic core 4 through the communication with the annular groove 613 at the joint of the magnetic core 4 and the framework 5, thereby eliminating the residual gap bubbles. The exhaust member 62 relies on the exhaust holes 621 at the highest position in the inside of the shell 1 to guide the gas discharged in the glue flowing process into the exhaust cavity 622 in the inner wall, and the gradually expanding structure can avoid the glue blockage of the exhaust holes 621, the gas is completely extracted in a vacuum environment through the exhaust main passage 623 arranged at an angle of 45° with the exhaust cavity 622, and the glue is potting without bubbles. The hemispherical main buffer cavity 631 and the secondary buffer cavity 632 of the buffer member 63 are respectively arranged on the bottom of the metal pin 2 and the inner top of the shell 1, when the equipment runs through temperature cycles, the volume change of the potting glue due to thermal expansion and cold contraction can be directionally deformed in the buffer cavities, the stress difference between the potting glue and the metal pin 2 and the magnetic core 4 can be absorbed, and the risk of glue cracking is further reduced through the cooperation of the toughening agent in the potting material.

[0053] The colloid flow path is as follows: after the glue solution is injected from the bottom injection port, it first fills the buffer cavity at the bottom of the metal pin 2, then flows into and fills the spiral main flow channel 611 at the bottom of the skeleton 5 and the branch flow channel 612 connected thereto, it should be noted that the cross section of the flow channel is V-shaped, then it penetrates and wraps the winding 3 from bottom to top, the glue solution completely fills all the tiny gaps between the coils of the winding 3 from bottom to top through the branch flow channel 612, ensuring that there is no dead angle wrapping, at the same time, the glue solution flows into and fills the annular flow channel, then the glue solution continues to rise and fills the main cavity between the winding 3 and the shell 1, and finally fills the buffer cavity at the top. During the whole process, the air displaced by the glue solution is always pushed to the highest point and is completely pumped out by the vacuum system through the top exhaust channel.

[0054] As shown in Figures 5 to 6 A vacuum heat-sealing structure of a current transformer and a manufacturing process thereof, comprising a shell 1, the inside of the shell 1 is provided with a metal pin 2, a winding 3 and a magnetic core 4 from bottom to top, the inside of the shell 1 is provided with an exhaust buffer unit 6, the exhaust buffer unit 6 comprises a flow guide 61, an exhaust member 62 and a buffer member 63:

[0055] The inside of the winding 3 is provided with a skeleton 5, the flow guide 61 is opened at the bottom of the skeleton 5, the flow guide 61 is used to guide the sealing glue to flow uniformly from bottom to top and completely wrap the winding 3, the exhaust member 62 is opened at the highest point inside the shell 1, the exhaust member 62 is used to exhaust the gas inside the shell 1 when the glue is filled, the buffer member 63 is arranged inside the shell 1, and the buffer member 63 is used to provide a directional deformation space when the sealing glue expands and contracts due to heat, so as to absorb and release internal stress.

[0056] Comprising the following steps:

[0057] S1, preparation of sealing material, preparation of modified epoxy resin composite material;

[0058] S2, internal mechanical mechanism processing of the shell 1, the flow guide 61 structure, the exhaust member 62 structure and the buffer member 63 structure are formed in the inside of the shell 1;

[0059] S3, vacuum sealing process, the sealing material is injected into the inside of the shell 1 under vacuum environment and solidified;

[0060] S4, product detection and verification, the solidified product is detected for insulation, heat conduction, mechanical and appearance performance.

[0061] The vacuum sealing process in step S3 comprises the following steps:

[0062] S31, preheating stage, put the shell into the heating box, preheat to 60-80°C, heat the potting adhesive to 50-60°C, reduce the viscosity of the glue to below 1000 cP, improve the fluidity;

[0063] S32, vacuum degassing, put the preheated shell into the vacuum chamber, vacuum to ≤100 Pa, keep for 15-20 minutes, completely extract the air and moisture in the gap between winding 3 and magnetic core 4;

[0064] S33, pressure injection, in a vacuum environment, inject potting adhesive from the bottom of the shell through a precision metering pump, the injection pressure is 0.1-0.3 MPa, the glue rises at a speed of 5-10 mm / min, ensuring that the air is discharged from the top exhaust member 62;

[0065] S34, step curing, using a programmed temperature curve, at 60°C for 2 hours for preliminary curing of the glue, then at 100°C for 4 hours for main body curing of the glue, and finally at 125°C for 2 hours for final solidification of the glue.

[0066] In this embodiment, the device first processes the internal mechanical mechanism of the shell 1, using a numerical control milling machine to process the flow guide 61, exhaust member 62 and buffer member 63 in the shell 1. Then enter the vacuum potting core process: first preheat the processed shell 1 to 60-80°C, heat the potting adhesive to 50-60°C to reduce the viscosity; then put the shell 1 into the vacuum chamber and vacuum to ≤100 Pa, keep for 15-20 minutes, extract the air and moisture in the gap between winding 3 and magnetic core 4; then inject glue from the bottom in a vacuum environment through a precision metering pump, control the injection pressure to 0.1-0.3 MPa, the glue rises at a speed of 5-10 mm / min, until no gas is discharged from the exhaust main channel 623; finally, use the step curing process, 60°C for 2 hours, 100°C for 4 hours, and 125°C for 2 hours, and then naturally cool to room temperature after curing. The finished product needs to be tested to ensure that the product meets the standards;

[0067] Insulation performance, pass the AC6kV voltage test for 1 minute without breakdown and flashover;

[0068] Thermal conductivity, ensure that the thermal conductivity coefficient is ≥1.5 W / m K, under the condition that the load current of the device is 1.2 times the rated value, the working temperature rise is ≤30°C;

[0069] Mechanical performance, after the potting body is cycled at -40°C to 85°C for 1000 times, the potting body has no cracking and the pins have no loosening;

[0070] The appearance quality is observed, the pouring sealant is ensured to be flat in surface, free of bubbles, glue deficiency and cracks, and the pouring sealant completely wraps the winding 3 and the magnetic core 4.

[0071] As shown in the drawings, the application discloses a vacuum heat pouring structure of a current transformer and a manufacturing process thereof. Figure 7 The vacuum heat pouring structure of the current transformer comprises a shell 1, a metal pin 2, a winding 3 and a magnetic core 4 arranged in the shell 1 from bottom to top, and an exhaust buffering unit 6 arranged in the shell 1.

[0072] The winding 3 is internally provided with a framework 5, the framework 5 is provided with a flow guide 61 at the bottom, the flow guide 61 is used for guiding the pouring sealant to flow uniformly from bottom to top and completely wrap the winding 3, the exhaust piece 62 is arranged at the highest position in the shell 1, the exhaust piece 62 is used for exhausting the gas in the shell 1 when the glue is poured, and the buffering piece 63 is arranged in the shell 1, the buffering piece 63 is used for providing a directional deformation space when the pouring sealant expands in heat and shrinks in cold, so as to absorb and release internal stress.

[0073] The pouring material preparation in the step S1 comprises the following steps.

[0074] S11, a batching stage, each component is prepared according to the following weight percentage, an epoxy resin matrix: 60-70wt%, a heat-conducting filler: 25-35wt%, a toughening agent: 3-5wt%, and a curing agent: 2-4wt%;

[0075] S12, preliminary mixing, the epoxy resin matrix and the heat-conducting filler are placed in a high-speed dispersion machine, and are stirred at a speed of 1500-2000rpm at 60-70℃ for 30-40 minutes, so that the epoxy resin matrix and the heat-conducting filler are fully mixed;

[0076] S13, toughening agent addition, the toughening agent is put into the mixture, the speed is reduced to 500-800rpm, and the mixture is stirred for 15-20 minutes, so that the filler is dispersed;

[0077] S14, curing agent addition, the mixture is put into a vacuum defoaming machine, then the curing agent is put into the mixture, the mixture is stirred at a speed of 300-500rpm at normal temperature for 10-15 minutes, and the glue is output in the condition of no bubbles;

[0078] S15, thixotropy detection, sample detection is carried out through a rotary viscometer, the glue is ensured to have a static viscosity of greater than or equal to 5000cP and a stirring viscosity of less than or equal to 1000cP, and the modified epoxy resin composite material meeting the requirements is poured into a sealed container for standby.

[0079] In this embodiment, in the mixing process, the epoxy resin and the heat-conducting filler are stirred at 60-70 DEG C and 1500-2000 rpm for 30-40 minutes, high-temperature and high-speed stirring can destroy the filler agglomerates, forming a continuous heat-conducting network; after adding the toughening agent, the stirring speed is reduced to 500-800 rpm for 15-20 minutes, low-speed stirring avoids the breakage of the toughening agent molecular chain; finally, the curing agent is added in a vacuum defoaming machine, and the stirring speed is 300-500 rpm at room temperature for 10-15 minutes, and the vacuum environment can eliminate the bubbles generated in the mixing process. Through thixotropy detection, it is ensured that the material has good fluidity when injecting glue, and finally forms a pouring material that takes into account heat conduction, insulation and toughness.

[0080] The epoxy resin matrix is selected from bisphenol A type epoxy resin, which provides basic insulation and bonding properties, the heat-conducting filler is selected from aluminum nitride or boron nitride or ceramic powder, which is uniformly dispersed to build a heat-conduction path, the toughening agent is selected from carboxyl-terminated nitrile rubber, which is used to improve the toughness of the material and reduce the curing internal stress, and the curing agent is selected from alicyclic amine curing agent, which is suitable for a ladder curing process and improves the curing uniformity.

[0081] Finally, it should be noted that: the above is only the preferred embodiment of the present application, and is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. A vacuum thermally conductive potting structure for a current transformer, comprising a housing (1), wherein metal pins (2), windings (3), and a magnetic core (4) are arranged from bottom to top inside the housing (1), characterized in that, The outer casing (1) is provided with an exhaust buffer unit (6), which includes a flow guide (61), an exhaust component (62), and a buffer component (63). The winding (3) is provided with a frame (5) inside. The flow guide (61) is opened at the bottom of the frame (5). The flow guide (61) includes a main flow channel (611) opened at the bottom of the frame (5) and a branch flow guide channel (612) opened on the frame (5). The main flow channel (611) is spirally designed and communicates with the branch flow guide channel (612). The width of the branch flow guide channel (612) is smaller than the width of the main flow channel (611). The flow guide (61) guides the potting compound to flow from bottom to top through the main flow channel (611) and delivers the compound to each layer of coil gap in the winding (3) through the branch flow guide channel (612). The venting element (62) is located at the highest point inside the outer shell (1). The venting element (62) is used to expel the gas inside the outer shell (1) during the filling of the colloid. The buffer element (63) is located inside the outer shell (1). The buffer element (63) is used to provide directional deformation space for the potting compound during thermal expansion and contraction, thereby absorbing and releasing internal stress.

2. The vacuum thermally conductive potting structure for a current transformer according to claim 1, characterized in that, The flow guide (61) also includes: The annular groove (613) is provided on the top of the frame (5), and the magnetic core (4) is provided on the top of the frame (5). The annular groove (613) is provided at the assembly joint of the magnetic core (4) and the frame (5). The annular groove (613) is connected to the branch guide groove (612).

3. The vacuum thermally conductive potting structure for a current transformer according to claim 1, characterized in that, The exhaust component (62) includes: Vent holes (621) are provided at the highest point inside the housing (1), and the vent holes (621) are arranged in an equidistant array; The exhaust chamber (622) is fixedly installed in the inner wall of the outer shell (1). The exhaust hole (621) is connected to the exhaust chamber (622). The exhaust chamber (622) has a tapered structure from bottom to top.

4. The vacuum thermally conductive potting structure for a current transformer according to claim 3, characterized in that, The exhaust component (62) also includes: The main exhaust channel (623) is located inside the outer casing (1). The main exhaust channel (623) communicates with the exhaust chamber (622) and the main exhaust channel (623) forms a 45° angle with the exhaust chamber (622).

5. The vacuum thermally conductive potting structure for a current transformer according to claim 1, characterized in that, The buffer (63) includes: The main buffer cavity (631) is located at the bottom of the metal pin (2). The bottom of the outer shell (1) is provided with a potting compound injection port. The main buffer cavity (631) is connected to the potting compound injection port and the main flow channel (611) respectively.

6. The vacuum thermally conductive potting structure for a current transformer according to claim 5, characterized in that, The buffer (63) also includes: The secondary buffer cavity (632) is located at the inner top of the outer shell (1), and the main buffer cavity (631) and the secondary buffer cavity (632) are in a hemispherical structure.

7. A manufacturing process for a vacuum thermally conductive potting structure of a current transformer, used to manufacture the vacuum thermally conductive potting structure of the current transformer according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Preparation of potting materials, preparation of modified epoxy resin composite materials; S2, The internal mechanical mechanism of the outer shell (1) is processed to form the flow guide (61) structure, the exhaust (62) structure and the buffer (63) structure inside the outer shell (1); S3, Vacuum potting process: The potting material is injected into the interior of the shell (1) under vacuum and then cured. S4. Finished product testing and verification: Insulation, thermal conductivity, mechanical properties and appearance of the cured product are tested.

8. The manufacturing process of a vacuum thermally conductive potting structure for a current transformer according to claim 7, characterized in that, The preparation of the potting material in step S1 includes the following steps: S11. In the batching stage, prepare each component according to the following weight percentages: epoxy resin matrix: 60-70wt%, thermally conductive filler: 25-35wt%, toughening agent: 3-5wt%, curing agent: 2-4wt%; S12. Preliminary mixing: Place the epoxy resin matrix and thermally conductive filler in a high-speed disperser and stir at 1500-2000 rpm for 30-40 minutes at 60-70℃ to ensure thorough mixing. S13. Add toughening agent: Add toughening agent to the mixture obtained in step S12, reduce the speed to 500-800 rpm, and stir for 15-20 minutes to ensure the filler is dispersed. S14. Adding curing agent: Put the mixture obtained in step S13 into a vacuum defoamer, then add the curing agent, and stir at 300-500 rpm at room temperature for 10-15 minutes. Output the colloid while ensuring no bubbles are present. S15. Thixotropic testing: Sampling tests are conducted using a rotational viscometer to ensure that the static viscosity of the colloid is ≥5000 cP and the stirring viscosity is ≤1000 cP. Modified epoxy resin composite materials that meet the requirements are then filled into sealed containers for later use.

9. The manufacturing process of a vacuum thermally conductive potting structure for a current transformer according to claim 7, characterized in that, The vacuum filling process in step S3 includes the following steps: S31. During the preheating stage, place the shell into the heating box and preheat it to 60-80°C. Heat the potting compound to 50-60°C to reduce the viscosity of the compound to below 1000 cP and improve its fluidity. S32. Vacuum degassing: Place the preheated shell into the vacuum chamber, evacuate to ≤100Pa, and maintain for 15-20 minutes to completely remove the air and moisture from the gap between the winding (3) and the magnetic core (4). S33, Pressure injection: In a vacuum environment, potting compound is injected from the bottom of the housing using a precision metering pump. The injection pressure is 0.1-0.3MPa, and the rising speed of the compound is 5-10mm / min. Ensure that air is discharged from the top exhaust component (62). S34. Step curing: Using a programmed temperature rise curve, the colloid is initially cured at 60℃ for 2 hours, then cured at 100℃ for 4 hours, and finally solidified at 125℃ for 2 hours.

Images