Combined mutual inductor

Abstract

The invention relates to the technical field of combined mutual inductors, and discloses a combined mutual inductor which comprises a main body shell, and a forced circulation cooling assembly, a suspension type fixing assembly, a full-sealed lead-out assembly and a pressure safety assembly which are arranged in the main body shell. The cooling assembly utilizes a pump body to actively drive insulating oil to be forced to circulate, so that efficient heat dissipation is realized; the suspension type fixing assembly isolates vibration through an elastic structure so as to protect the metering iron core and guarantee the metering precision. The fully-sealed lead-out assembly adopts a rigid-flexible composite structure to reliably seal a lead-out wire and buffer mechanical stress; the pressure safety assembly can achieve safety pressure relief after oil-gas separation when the internal high pressure is abnormal. The problems that an existing combined transformer is low in heat dissipation efficiency, the metering precision is prone to being affected, the sealing performance is poor and active safety protection is insufficient are comprehensively solved, the operation stability, the metering precision, the sealing reliability and the overall safety level of equipment are remarkably improved, and the service life of the combined transformer is prolonged.

Description

Technical Field

[0001] This invention relates to the field of combined current transformer technology, and in particular to combined current transformers. Background Technology

[0002] Combined instrument transformers are devices used in power systems to transform voltage and current. Their output secondary signals are used for energy metering and relay protection. The operational performance, measurement accuracy, and structural integrity of the equipment are the basic technical requirements for its application.

[0003] In existing technologies, combined instrument transformers generate heat during operation due to losses in the internal windings and core. Current heat dissipation methods rely partly on natural convection of the insulating medium and radiation from the casing, which have limited heat transfer coefficients. When the equipment load is high or the ambient temperature is high, the internal temperature of the equipment rises, resulting in an uneven temperature distribution. This temperature rise accelerates the chemical decomposition rate of the solid insulating material and insulating oil, reducing the dielectric strength of the insulation system. Another approach involves forced cooling systems using oil pumps or fans, but this increases the number of auxiliary components, external energy consumption, and the frequency of operation and maintenance.

[0004] To ensure its metering function, the metering core inside the instrument transformer must maintain stable magnetic properties. The currently commonly used rigid fixed structure will directly transmit stress to the metering core when the equipment is subjected to external mechanical vibration or electrodynamic impact, causing changes in the magnetostrictive properties of the core material. This, in turn, leads to changes in the transformer's ratio error and angular error, causing its metering accuracy to deviate over time or under specific operating conditions.

[0005] The equipment's lead wires must pass through the main housing; the sealing structure here prevents leakage of internal insulating oil and intrusion of external moisture. Existing seals are subjected to alternating mechanical stresses under the temperature-changing cycles and continuous mechanical vibrations of the equipment during operation. This can cause fatigue, creep, or physical aging of the sealing material, leading to gaps at the sealing interface, compromising the integrity of the seal, and consequently causing leakage or moisture absorption of the insulating medium, thus affecting the equipment's insulation performance.

[0006] Furthermore, when a fault such as a short circuit occurs inside the equipment, the instantaneous release of energy can cause a sharp rise in internal pressure. Existing pressure relief devices, when activated, typically open a channel directly to the external environment. This causes the high-pressure gas and high-temperature insulating oil mixture inside to be discharged together, resulting not only in the loss of the insulating medium but also in the flammable oil mist, posing a potential safety hazard to the surrounding environment and equipment. Summary of the Invention

[0007] The purpose of this invention is to provide a combined current transformer that solves the problems of existing combined current transformers, such as complex heat dissipation structure, high energy consumption and uneven internal temperature field, the metering core being susceptible to vibration and shock leading to decreased measurement accuracy, poor reliability of the sealing structure of the lead wire section which is prone to failure due to stress, and the lack of an active and safe pressure relief protection mechanism under extreme fault conditions.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A combined current transformer includes a main housing and a coil. A forced circulation cooling assembly is provided inside the main housing to drive the insulating oil to perform thermosiphon self-circulation in a fully sealed state. A heat collection assembly is provided inside the main housing to collect the overall heat to assist the forced circulation cooling assembly in circulating cooling. The inner side of the main body shell is provided with multiple floating fixing components for firmly fixing the coil and suspending and positioning the metering iron core inside the coil, so as to protect the magnetic properties of the iron core and ensure its metering accuracy. The output end of the coil is provided with a fully sealed lead-out component for electrically connecting and sealing the lead-out wires from the coil. A pressure safety component is provided on the inner top side of the main body shell to provide an active, multi-stage safety pressure relief channel for the entire device. The self-closed circulation cooling assembly includes a bellows, which is fixedly connected to the inner sides of both ends of the top of the main body shell. A pump body is installed inside one end of the bellows. Two sealed cavities are fixedly connected to the inner side of the bellows. The bellows is connected to both ends of the sealed cavities. A fixing plate is fixedly connected to the inner side of the main body shell. Windings are fixedly connected to both ends of the fixing plate. Both windings are located on the outer sides of both ends of the bellows.

[0009] Preferably, the heat collection assembly includes an oil collecting funnel, which is fixedly connected to the top inner side of the main body shell. Both ends of the corrugated pipe are fixedly connected to conduits. The end of the conduit away from the winding is fixedly connected to the inner side of the oil collecting funnel, and the coil is disposed on the outer side of the bottom of the oil collecting funnel.

[0010] Preferably, the fixing component includes a limiting block one, which is fixedly connected to the inner side of the main body shell. A positioning ring is provided on the outer side of the coil, and an installation block is fixedly connected to the outer side of the positioning ring. An alloy skeleton is fixedly connected to the inner side of the limiting block one and the installation block, and a silicone rubber gasket is provided on the outer side of the alloy skeleton.

[0011] Preferably, the fully sealed lead-out assembly includes multiple connecting blocks, the coil output end is connected to multiple lead-out wires, the ends of two lead-out wires away from the positioning ring are merged together, a fixing block is fixedly connected to the side of the main body shell, and two rubber sleeves are fixedly connected to the inner side of the fixing block, and the two rubber sleeves are respectively sleeved on the outside of the two merged lead-out wires.

[0012] Preferably, the fully sealed lead-out assembly further includes a sealing tube, which is fixedly connected to the inner side of the fixing block. The two combined lead-out wires and rubber sleeves are all disposed inside the sealing tube. An inner layer of epoxy resin is fixedly connected to one end of the sealing tube away from the fixing block. An outer layer of silicone rubber is fixedly connected to the outer side of the inner layer of epoxy resin. Two sealing rubber plates are also fixedly connected to the outer side of the inner layer of epoxy resin.

[0013] Preferably, the pressure safety component includes a valve, which is fixedly connected to the top inner side of the main body shell. Limiting rods are fixedly connected to both sides of the valve. A lower metal plate is fixedly connected to the top of the valve. Limiting blocks are fixedly connected to both sides of the lower metal plate. The two limiting rods are slidably connected to the inner sides of the two limiting blocks. A lower metal plate is fixedly connected to the side of the lower metal plate. An upper metal plate is fixedly connected to the top of the lower metal plate. A flow guiding chamber is fixedly connected to the side of the upper metal plate away from the filter pack. A flow guiding nozzle is fixedly connected to the inner side of the flow guiding chamber. A rainproof and dustproof cover is fixedly connected to the outer side of the end of the flow guiding nozzle away from the flow guiding chamber.

[0014] Preferably, a sealing shell is fixedly connected to the outside of the fixing block, and the sealing shell is fixedly connected to the outside of the main body shell. The sealing tube, the outer silicone rubber, the sealing rubber plate and the inner epoxy resin are all disposed on the inside of the sealing shell. A flange is fixedly connected to the outside of the end of the inner epoxy resin away from the sealing tube, and the flange is disposed on the outside of the sealing shell.

[0015] Preferably, a heat sink is fixedly connected to the top of the main body shell, and multiple heat sink blocks are fixedly connected to the outside of the heat sink. Multiple heat sinks are also fixedly connected to the outside of the two sealed cavities.

[0016] Preferably, a base is provided on the bottom side of the main body shell, and fixing bolts are provided on the bottom of the main body shell and the inner side of the base.

[0017] Preferably, the oil collecting funnel contains insulating oil, which circulates between the two conduits and the corrugated pipe.

[0018] In summary, the present invention has at least one of the following beneficial technical effects: 1. This invention, by setting up a forced circulation cooling component, utilizes a pump to actively drive the insulating oil to circulate at high speed within a circuit formed by a bellows and a conduit. Compared to traditional natural cooling or thermosiphon effect, this active cooling can more quickly and efficiently remove the heat generated by the windings and coils, and, in conjunction with the heat sink and heat dissipation block, quickly dissipate the heat, thereby achieving strong control over the internal temperature of the equipment. In particular, it can meet the heat dissipation requirements under high load conditions, ensuring the operational stability and service life of the equipment.

[0019] 2. This invention uses a suspended fixing component to utilize the elastic buffering properties of silicone rubber gaskets, along with an alloy skeleton and positioning rings, to provide a stable and shock-absorbing suspended positioning for the coil. This effectively isolates the core metering components from external vibrations and impacts, protecting the magnetic properties of the internal metering core from damage over the long term, thereby significantly improving the metering accuracy and reliability of the measurement results of the combined current transformer.

[0020] 3. By adding a pressure safety component, this invention can provide an active and multi-stage safety pressure relief scheme in extreme cases where abnormally high pressure occurs inside the equipment. When the pressure exceeds the limit, the valve opens, and when the high-pressure oil-gas mixture passes through the filter screen, the oil droplets are effectively filtered and intercepted, allowing only the gas to be safely discharged through the guide nozzle pipe. This avoids the insulating oil splashing and environmental pollution that can occur with traditional pressure relief methods, and greatly improves the active safety protection level of the equipment. Attached Figure Description

[0021] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the sealed cavity structure of the present invention; Figure 3 This is a schematic diagram of the bellows structure of the present invention; Figure 4 This is a schematic diagram of the silicone rubber gasket structure of the present invention; Figure 5 This is a schematic diagram of the lead wire structure of the present invention; Figure 6 This is a schematic diagram of the alloy skeleton structure of the present invention; Figure 7 This is a schematic diagram of the valve structure of the present invention; Figure 8 This is a schematic diagram of the flow guiding chamber structure of the present invention; Figure 9 for Figure 8 Enlarged view of A in the middle; Figure 10 for Figure 8 A magnified view of B in the middle.

[0022] The components are as follows: 1. Main body shell; 2. Heat dissipation shell; 3. Base; 4. Fixing bolts; 5. Sealing shell; 6. Limiting block one; 7. Winding; 8. Bellows; 9. Sealing cavity; 10. Pump body; 11. Alloy skeleton; 12. Positioning ring; 13. Lead wire; 14. Oil collection funnel; 15. Fixing plate; 16. Conduit; 17. Coil; 18. Silicone rubber gasket; 19. Connecting block; 20. Rubber sleeve; 21. Fixing block; 22. Sealing tube; 23. Outer silicone rubber; 24. Sealing rubber plate; 25. Inner epoxy resin; 26. Mounting block; 27. Heat dissipation block; 28. Flange; 29. ​​Valve; 30. Limiting rod; 31. Limiting block two; 32. Lower metal plate; 33. Filter pack; 34. Upper metal plate; 35. Flow guiding chamber; 36. Flow guiding nozzle pipe; 37. Rainproof and dustproof cover. Detailed Implementation

[0023] The following is in conjunction with the appendix Figure 1 -Appendix Figure 10 The present invention will be further described in detail below.

[0024] The present invention provides a combined current transformer, including a main housing 1 and a coil 17. A forced circulation cooling assembly is provided inside the main housing 1 for driving the insulating oil to perform thermosiphon self-circulation in a fully sealed state. A heat collection assembly is provided inside the main housing 1 for collecting the overall heat to assist the forced circulation cooling assembly in circulating cooling. Multiple suspended fixing components are provided inside the main body shell 1 to stabilize and fix the coil 17 and the metering iron core inside the suspended positioning coil 17, so as to protect the magnetic properties of the iron core and ensure its metering accuracy. The output end of the coil 17 is provided with a fully sealed lead-out component for electrical connection and all-round sealing of the lead-out wires led out from the coil 17. A pressure safety component is provided on the top inner side of the main body shell 1 to provide an active, multi-stage safety pressure relief channel for the entire equipment; The self-closed circulation cooling assembly includes a bellows 8, which is fixedly connected to the inner sides of both ends of the top of the main body shell 1. A pump body 10 is installed inside one end of the bellows 8. Two sealed cavities 9 are fixedly connected to the inner side of the bellows 8. The bellows 8 is connected to the two ends of the sealed cavities 9. A fixing plate 15 is fixedly connected to the inner side of the main body shell 1. Windings 7 are fixedly connected to both ends of the fixing plate 15. Both windings 7 are located on the outer sides of both ends of the bellows 8.

[0025] Specifically, the main body shell 1 is a sealed container used to house and isolate all internal functional components and insulating oil, separating them from the external environment. Simultaneously, the main body shell 1 provides a stable base for external heat dissipation, fixation, and sealing components. The coil 17 operates based on the principle of electromagnetic induction. Its primary side senses the voltage or current of the power grid, and its secondary side outputs a voltage or current signal for measurement or protection according to a predetermined transformation ratio. When energized, its windings generate Joule heat due to their own resistance, constituting a heat source inside the equipment. The forced circulation cooling component applies mechanical work to the insulating oil through the pump body 10, driving the insulating oil to circulate at a specific flow rate in a set closed loop. This process removes heat from the windings. At heat sources such as group 7 and coil 17, heat is transferred to the heat collection assembly and main shell 1 via insulating oil. The heat collection assembly collects the insulating oil carrying heat flowing from the circulation pipeline and guides it to the inner wall of the main shell 1 to increase the contact area and time for heat exchange, thereby conducting the heat to the external heat dissipation structure. The suspended fixing assembly uses its internal rigid components to spatially position coil 17, while its elastic components form a connection with specific damping and vibration reduction characteristics between the rigid components and coil 17 or main shell 1. This connection is used to attenuate the external mechanical vibration transmitted to the metering core, thereby maintaining the stability of the core's permeability. To ensure the accuracy of the metering ratio; the fully sealed lead-out assembly forms a seal at the interface where the lead-out line 13 penetrates the main body shell 1, preventing the exchange of gas and liquid. Its internal hard sealing material provides airtightness, while the external flexible material absorbs stress caused by thermal expansion differences and mechanical vibration, preventing stress concentration from causing seal failure; the pressure safety assembly opens its valve to form a pressure relief channel when the internal pressure exceeds a preset threshold. The outflowing oil-gas mixture undergoes phase separation as it passes through the internal filter, with the gas phase being discharged and the liquid phase being retained, thereby reducing the risk of structural damage to the shell due to overpressure; the bellows 8 serves as a section in the cooling circuit that can generate... The elastically deformable pipe is used to compensate for alignment deviations and thermal expansion and contraction that occur in the piping system during installation or operation; the pump body 10 is a mechanical device that performs work on the insulating oil after being energized to generate a pressure difference, which is the direct power driving the insulating oil to flow in the cooling circuit; the sealed cavity 9 is a rigid pipe part in the cooling circuit, connected to the bellows 8, together defining a closed channel for the circulation of insulating oil; the fixed plate 15 is a structural support component that provides a reference surface with a defined position and orientation for the installation of the winding 7; the winding 7 carries current, and the heat generated by the resistance when the current flows through its conductor is the main heat load that the forced circulation cooling assembly needs to remove.

[0026] Please see the appendix Figure 2 -Appendix Figure 4The heat collection assembly includes an oil collection funnel 14, which is fixedly connected to the top inner side of the main body shell 1. Both ends of the corrugated pipe 8 are fixedly connected to conduits 16. The end of the conduit 16 away from the winding 7 is fixedly connected to the inner side of the oil collection funnel 14. The coil 17 is located on the outer side of the bottom of the oil collection funnel 14.

[0027] Specifically, the oil collecting funnel 14 is used to collect the medium from the conduit 16 and provide a mounting location for the coil 17; the conduit 16 is used to conduct the heat collected by the bellows 8 to the oil collecting funnel 14; the coil 17 is used to heat the medium in the oil collecting funnel 14 or utilize its heat; the bellows 8 is used to surround the heat source in order to efficiently absorb heat.

[0028] Please see the appendix Figure 2 Appendix Figure 4 and attached Figure 6 The fixing component includes a limiting block 6, which is fixedly connected to the inner side of the main body shell 1. A positioning ring 12 is provided on the outer side of the coil 17. An installation block 26 is fixedly connected to the outer side of the positioning ring 12. An alloy skeleton 11 is fixedly connected to the inner side of the limiting block 6 and the installation block 26. A silicone rubber gasket 18 is provided on the outer side of the alloy skeleton 11.

[0029] Specifically, the limiting block 6 is used to limit the position of the alloy skeleton 11 to prevent unnecessary displacement; the positioning ring 12 is used to circumferentially position the coil 17 and provide a connection base for the mounting block 26; the mounting block 26 is used to connect the positioning ring 12 and the alloy skeleton 11, which plays a role in stabilizing the installation; the alloy skeleton 11 is used as the core support structure to connect the limiting block 6 and the mounting block 26, ensuring the structural strength and stability of the entire fixing assembly; the silicone rubber gasket 18 is used to provide buffering and shock absorption, absorb the vibration generated during equipment operation, and protect the internal components.

[0030] Please see the appendix Figure 4 and attached Figure 5The fully sealed lead-out assembly includes multiple connecting blocks 19. Multiple lead wires 13 are connected to the output end of the coil 17. The ends of two lead wires 13 furthest from the positioning ring 12 are joined together. A fixing block 21 is fixedly connected to the side of the main body shell 1. Two rubber sleeves 20 are fixedly connected to the inner side of the fixing block 21, and the two rubber sleeves 20 are respectively fitted onto the outside of the two joined lead wires 13. The fully sealed lead-out assembly also includes a sealing tube 22, which is fixedly connected to the inner side of the fixing block 21. The two joined lead wires 13 and the rubber sleeves 20 are all located inside the sealing tube 22. An inner layer of epoxy resin 25 is fixedly connected to the end of the sealing tube 22 furthest from the fixing block 21. An outer layer of silicone rubber 23 is fixedly connected to the outside of the inner layer of epoxy resin 25. Two sealing rubber plates 24 are also fixedly connected to the outside of the inner layer of epoxy resin 25. A sealing shell 5 is fixedly connected to the outside of the fixing block 21. The sealing shell 5 is fixedly connected to the outside of the main body shell 1. The sealing tube 22, the outer silicone rubber 23, the sealing rubber plate 24, and the inner epoxy resin 25 are all disposed on the inside of the sealing shell 5. A flange 28 is fixedly connected to the outside of the end of the inner epoxy resin 25 away from the sealing tube 22. The flange 28 is disposed on the outside of the sealing shell 5.

[0031] Specifically, lead wire 13 is used to lead the electrical signal or energy inside coil 17 from the inside of the main body housing 1 to the outside. Fixing block 21 provides a stable mounting base on the main body housing 1 for installing and securing subsequent sealing structures. Rubber sleeve 20 provides initial insulation and protection for lead wire 13 and enhances its tightness with subsequent sealing materials. Sealing tube 22 constructs a sealed channel to accommodate the lead wire and rubber sleeve, and serves as a cavity for filling sealing material. Inner epoxy resin 25 fills the interior of sealing tube 22, and after curing, forms a hard and dense sealing body, achieving a core airtight and waterproof encapsulation of the lead wire. Outer silicone rubber 23 wraps around the epoxy resin, utilizing its elasticity to provide secondary sealing protection, while also acting as a buffer for shock absorption and adapting to thermal expansion and contraction. Sealing rubber plate 24 further enhances the sealing performance of the assembly by filling any small gaps through compression deformation. The sealing housing 5 provides a unified external physical protection for complex internal sealing structures such as sealing tubes, epoxy resin, and silicone rubber, preventing them from mechanical damage. The flange 28 provides a standard mechanical connection interface, enabling the entire fully sealed lead-out assembly to easily and reliably connect to external equipment or pipelines, ensuring a tight seal at the connection point.

[0032] Please see the appendix Figure 7 -Appendix Figure 10The pressure safety component includes a valve 29, which is fixedly connected to the top inner side of the main body shell 1. Limit rods 30 are fixedly connected to both sides of the valve 29. A lower metal plate 32 is fixedly connected to the top of the valve 29. Limit blocks 31 are fixedly connected to both sides of the lower metal plate 32. The two limit rods 30 are slidably connected to the inner sides of the two limit blocks 31 respectively. A lower metal plate 32 is fixedly connected to the side of the lower metal plate 32. An upper metal plate 34 is fixedly connected to the top of the lower metal plate 32. A flow guiding chamber 35 is fixedly connected to the side of the upper metal plate 34 away from the filter pack 33. A flow guiding nozzle pipe 36 is fixedly connected to the inner side of the flow guiding chamber 35. A rainproof and dustproof cover 37 is fixedly connected to the outer side of the end of the flow guiding nozzle pipe 36 away from the flow guiding chamber 35.

[0033] Specifically, valve 29, as the core of the pressure safety component, is used to automatically open when the internal pressure of the equipment exceeds a preset safety threshold, releasing the high-pressure oil-gas mixture inside. The lower metal plate 32 and the upper metal plate 34 together form a processing chamber, providing an installation foundation and structural support for the filter pack and subsequent airflow guidance. The sliding engagement between the limit rod 30 and the limit block 31 guides valve 29 to perform stable and linear reciprocating motion during opening and closing, preventing it from jamming. The filter pack 33 is used to efficiently separate the oil-gas mixture that rushes out during the pressure relief process. Its complex multi-stage labyrinth structure can effectively intercept and condense oil droplets, causing the insulating oil to fall back, while only allowing gas to pass through. The flow guiding chamber 35 is used to collect the pure gas separated by the filter. The flow guiding nozzle 36 is used to guide the collected gas and discharge it to the outside of the equipment in a safe direction and speed. The rainproof and dustproof cover 37 is used to protect the outlet of the flow guiding nozzle 36, preventing rainwater, dust and other external impurities from entering the pressure safety component, ensuring that it is always in a normal standby state.

[0034] Please see the appendix Figure 1 -Appendix Figure 3 A heat sink 2 is fixedly connected to the top of the main body shell 1. Multiple heat sink blocks 27 are fixedly connected to the outside of the heat sink 2. Multiple heat sink fins are also fixedly connected to the outside of the two sealed cavities 9. A base 3 is provided on the bottom side of the main body shell 1. Fixing bolts 4 are provided on the bottom of the main body shell 1 and the inside of the base 3. The oil collecting funnel 14 collects insulating oil, which circulates between two conduits 16 and a corrugated pipe 8.

[0035] Specifically, the main shell 1 is used to protect the internal components and provide a mounting base for components such as the heat sink 2 and the base 3; the heat sink 2, heat dissipation block 27, and heat sink fins are all used to increase the contact area between the device and the outside air, thereby improving heat dissipation efficiency and accelerating the cooling speed of the internal insulating oil; the base 3 is used to provide stable support for the entire device; the fixing bolts 4 are used to fasten the main shell 1 and the base 3 to ensure the stability of the overall structure; the oil collecting funnel 14 is used to collect and store the insulating oil as a cooling medium; the insulating oil is used to absorb the heat generated by the internal components during circulation and conduct it to the external heat dissipation components; the conduit 16 and the bellows 8 together form the circulation loop of the insulating oil, wherein the bellows 8 can also compensate for thermal expansion and contraction caused by changes in oil temperature.

[0036] Working Principle: First, the core thermal management of the equipment relies on a forced circulation cooling assembly. Its core driving force is provided by the pump body 10. When the equipment is running, the pump body 10 starts, actively pumping insulating oil, which serves as the cooling medium, into the circulation loop formed by the bellows 8, conduit 16, and sealed cavity 9. Under the forced drive of the pump, the insulating oil flows at a high velocity around the windings 7 and coils 17, the main heat sources, thereby absorbing the heat generated by the windings 7 and coils 17 during operation. The insulating oil carrying a large amount of heat is delivered by the pump body 10 to the oil collection funnel 14 at the top of the equipment and the circulation pipeline. The heat absorbed by the insulating oil is transferred to the surrounding environment through the main shell 1 and external structures such as the heat sink 2, heat dissipation block 27, and heat sink fins. The cooled insulating oil continues to flow in the loop and is again drawn in and pressurized by the pump body 10, thus forming a closed-loop circulation of the insulating oil within the forced circulation cooling assembly. This active circulation method driven by the pump body 10 has higher cooling efficiency than traditional natural cooling or thermosiphon effect. It can remove the heat generated by the core components more quickly, thereby more effectively balancing the internal temperature field of the equipment and providing thermal management protection for the equipment during operation.

[0037] Meanwhile, to ensure the accuracy of the metering equipment, the suspended fixing assembly provides protection. The suspended fixing assembly uses the limiting block 6 as the overall fixing point, and utilizes rigid structures such as the alloy frame 11, positioning ring 12, and mounting block 26 to stably fix and position the coil 17. It utilizes elastic silicone rubber gaskets 18 to achieve a suspended buffer positioning of the coil 17 and its highly sensitive metering core. This effectively absorbs and isolates vibrations from power grid impacts or external environments, preventing mechanical stress from being directly transmitted to the metering core, thereby fundamentally protecting the magnetic properties of the core and ensuring the metering accuracy of the transformer.

[0038] Meanwhile, the fully sealed lead-out assembly addresses weak points in the equipment's electrical connections. It achieves a seal at the point where the lead-out wire 13 passes through the main housing 1 via a precision structure protected by a fixing block 21 and an outer sealing shell 5. The lead-out wire is initially protected by a rubber sleeve 20, followed by rigid and dense encapsulation by an inner layer of epoxy resin 25, achieving core airtightness. Then, an outer layer of silicone rubber 23 provides flexible buffering and a secondary seal, further enhanced by a sealing rubber plate 24. This not only prevents insulating oil leakage and external moisture intrusion but also adaptively buffers and absorbs stress generated by temperature changes and mechanical vibrations, avoiding seal failure due to stress concentration and improving the long-term reliability of the equipment under complex operating conditions. Finally, a flange 28 enables safe connection to the external environment.

[0039] Finally, the pressure safety component provides the ultimate safety guarantee for the equipment. In the event of an extreme fault such as an internal short circuit causing a sudden pressure surge, valve 29 will automatically open at a preset pressure and move stably under the guidance of limit rod 30 and limit block 31. When the high-pressure oil-gas mixture rushes out, it must pass through filter screen 33, whose structure effectively separates the oil and gas, intercepts insulating oil droplets and causes them to fall back, ensuring that only pure gas is safely discharged through the guide chamber 35 and guide nozzle pipe 36. While ensuring the structural safety of the equipment, it avoids environmental pollution and fire risks caused by insulating oil splashing, comprehensively improving the active safety protection level of the equipment.

Claims

1. A combined current transformer, characterized in that, It includes a main shell (1) and a coil (17). The inner side of the main shell (1) is provided with a forced circulation cooling component for driving the insulating oil to perform thermosiphon self-circulation in a fully sealed state. The inner side of the main shell (1) is provided with a heat collection component for collecting the overall heat to assist the forced circulation cooling component in circulating cooling. The inner side of the main body shell (1) is provided with multiple floating fixing components for the purpose of firmly fixing the coil (17) and suspending and positioning the metering iron core inside the coil (17) to protect the magnetic properties of the iron core and ensure its metering accuracy. The output end of the coil (17) is provided with a fully sealed lead-out component for the purpose of electrically connecting and sealing the lead-out wires led out from the coil (17). The main body shell (1) is provided with a pressure safety component on the top inner side, which is used to provide an active, multi-stage safety pressure relief channel for the whole equipment; The self-closed circulation cooling assembly includes a bellows (8), which is fixedly connected to the inner sides of both ends of the top of the main body shell (1). A pump body (10) is provided inside one end of the bellows (8). Two sealed cavities (9) are fixedly connected to the inner side of the bellows (8). The bellows (8) is connected to both ends of the sealed cavities (9). A fixing plate (15) is fixedly connected to the inner side of the main body shell (1). Both ends of the fixing plate (15) are fixedly connected to windings (7). Both windings (7) are located on the outer sides of both ends of the bellows (8).

2. The combined current transformer according to claim 1, characterized in that, The heat collection assembly includes an oil collection funnel (14), which is fixedly connected to the top inner side of the main body shell (1). Both ends of the corrugated pipe (8) are fixedly connected to conduits (16). The end of the conduit (16) away from the winding (7) is fixedly connected to the inner side of the oil collection funnel (14). The coil (17) is located on the outer side of the bottom of the oil collection funnel (14).

3. The combined current transformer according to claim 1, characterized in that, The fixing component includes a limiting block (6), which is fixedly connected to the inner side of the main body shell (1). A positioning ring (12) is provided on the outer side of the coil (17), and an mounting block (26) is fixedly connected on the outer side of the positioning ring (12). An alloy skeleton (11) is fixedly connected on the inner side of the limiting block (6) and the mounting block (26), and a silicone rubber gasket (18) is provided on the outer side of the alloy skeleton (11).

4. The combined current transformer according to claim 3, characterized in that, The fully sealed lead-out assembly includes multiple connecting blocks (19), and the output end of the coil (17) is connected to multiple lead-out wires (13). The ends of two lead-out wires (13) away from the positioning ring (12) are joined together. A fixing block (21) is fixedly connected to the side of the main body shell (1). Two rubber sleeves (20) are fixedly connected to the inside of the fixing block (21). The two rubber sleeves (20) are respectively sleeved on the outside of the two joined lead-out wires (13).

5. The combined current transformer according to claim 4, characterized in that, The fully sealed lead-out assembly also includes a sealing tube (22), which is fixedly connected to the inside of the fixing block (21). The two combined lead-out wires (13) and the rubber sleeve (20) are all located inside the sealing tube (22). An inner layer of epoxy resin (25) is fixedly connected to one end of the sealing tube (22) away from the fixing block (21). An outer layer of silicone rubber (23) is fixedly connected to the outside of the inner layer of epoxy resin (25). Two sealing rubber plates (24) are also fixedly connected to the outside of the inner layer of epoxy resin (25).

6. The combined current transformer according to claim 5, characterized in that, The pressure safety component includes a valve (29), which is fixedly connected to the top inner side of the main body shell (1). Limit rods (30) are fixedly connected to both sides of the valve (29). A lower metal plate (32) is fixedly connected to the top of the valve (29). Limit blocks (31) are fixedly connected to both sides of the lower metal plate (32). The two limit rods (30) are slidably connected to the inner sides of the two limit blocks (31). A lower metal plate (32) is fixedly connected to the side of the lower metal plate (32). An upper metal plate (34) is fixedly connected to the top of the lower metal plate (32). A flow guiding chamber (35) is fixedly connected to the side of the upper metal plate (34) away from the filter bag (33). A flow guiding nozzle pipe (36) is fixedly connected to the inner side of the flow guiding chamber (35). A rainproof and dustproof cover (37) is fixedly connected to the outer side of the end of the flow guiding nozzle pipe (36) away from the flow guiding chamber (35).

7. The combined current transformer according to claim 1, characterized in that, A sealing shell (5) is fixedly connected to the outside of the fixing block (21). The sealing shell (5) is fixedly connected to the outside of the main body shell (1). The sealing tube (22), the outer silicone rubber (23), the sealing rubber plate (24) and the inner epoxy resin (25) are all disposed on the inside of the sealing shell (5). A flange (28) is fixedly connected to the outside of the end of the inner epoxy resin (25) away from the sealing tube (22). The flange (28) is disposed on the outside of the sealing shell (5).

8. The combined current transformer according to claim 1, characterized in that, The main body shell (1) is fixedly connected to a heat sink shell (2) at the top, and multiple heat sink blocks (27) are fixedly connected to the outside of the heat sink shell (2). Multiple heat sinks are also fixedly connected to the outside of the two sealed cavities (9).

9. The combined current transformer according to claim 1, characterized in that, A base (3) is provided on the bottom side of the main body shell (1), and fixing bolts (4) are provided on the bottom of the main body shell (1) and the inner side of the base (3).

10. The combined transformer according to claim 2, wherein insulating oil is collected inside the oil collecting funnel (14), and the insulating oil circulates between the two conduits (16) and the corrugated pipe (8).

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