Single-phase ground fault detection combined transformer

Abstract

The application discloses a single-phase grounding fault detection combined transformer, relates to the technical field of combined transformers, and realizes a suspension installation form of a transformer body without rigid fixation, wherein a floating gap is reserved between the transformer body and the shell and the damping structure in a normal state, internal pouring stress generated due to temperature expansion and contraction and equipment vibration in a traditional transformer rigid fixation mode can be effectively avoided, problems such as cracking of an epoxy resin shell, internal core deviation and winding loosening are avoided, the structure relies on vibration displacement of the transformer to trigger hydraulic transmission, bilateral synchronous damping is realized, the greater the vibration, the stronger the hydraulic clamping force, high-frequency and impact vibration generated during work can be effectively absorbed, unilateral deviation and unilateral extrusion deformation do not occur, after the vibration disappears, the first spring can be automatically reset to release pressure, the flexible block is separated from the outer wall of the transformer, the suspension gap is restored, and the deformation allowance of the transformer body due to thermal expansion and cold contraction is reserved for a long time.

Description

Technical Field

[0001] This invention relates to the field of combined instrument transformer technology, specifically to a combined instrument transformer for detecting single-phase grounding faults. Background Technology

[0002] In the existing technology, box-type combined instrument transformers used for single-phase grounding fault detection in distribution networks generally adopt an integral rigid welded fixed structure. There is no floating buffer gap between the instrument transformer casting body and the outer metal shell. The frequent opening and closing of the pole-mounted vacuum switch generates continuous impact vibration. The vibration is directly transmitted to the PT and CT cores and windings inside the instrument transformer, which can easily cause core displacement, loosening of winding leads, and deviation of three-phase electromagnetic parameters. Under no-load conditions, it generates false zero-sequence voltage and zero-sequence current with large amplitude, causing the distribution terminal to misjudge the grounding fault. Meanwhile, the rigid fixed structure cannot offset the difference in thermal expansion between the epoxy resin casting and the metal shell. Long-term outdoor high and low temperature cycles will cause the casting to crack and the internal insulation to decrease, further deteriorating the acquisition accuracy of weak grounding fault signals. Existing vibration reduction methods are mostly fixed inside the shell with a single rubber pad, compression spring and other constant damping buffer components. The buffer clamping force cannot be adaptively adjusted with the vibration intensity, making it difficult to achieve high-precision and stable acquisition of zero-sequence signals.

[0003] The existing technical solutions have obvious limitations in practice: traditional instrument transformers directly and rigidly fasten the instrument transformer body and the outer shell together with bolts and brackets. There is no floating buffer gap between the body and the shell. The impact vibration generated by the opening and closing of the pole-mounted switch will be completely transmitted to the inside of the instrument transformer. Under continuous vibration, problems such as core displacement, loosening of winding leads and stress cracking of epoxy resin casting are likely to occur, which can easily cause frequent false alarms of single-phase grounding faults in the distribution terminal. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a combined instrument transformer for single-phase grounding fault detection. This solves the problem mentioned in the background section where traditional instrument transformers rigidly fasten the transformer body and the outer casing together with bolts and brackets, leaving no floating buffer gap between the body and the casing. The impact vibration generated by the opening and closing of the pole-mounted switch is completely transmitted to the inside of the instrument transformer. Under continuous vibration, problems such as core displacement, loosening of winding leads, and stress cracking of the epoxy resin casting are likely to occur, which can easily lead to frequent false alarms of single-phase grounding faults in the distribution terminal.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a combined instrument transformer for single-phase ground fault detection, comprising a housing, an instrument transformer body, an interface, and a mitigation mechanism; the mitigation mechanism includes a first sealing cylinder, a first piston rod, a trigger pad, a connecting pipe, a guide vane, a protective cylinder, a second sealing cylinder, a second piston rod, a flexible block, a first spring, and a contact block; the first sealing cylinder is fixedly assembled inside the housing, the first piston rod is vertically slidably and sealingly installed inside the first sealing cylinder, the trigger pad is fixedly assembled at the top of the first piston rod, the connecting pipe is fixedly arranged inside the housing, and the connecting pipe is sealed and filled with a pressure-transmitting liquid; the connecting pipe's... One end of the pipeline cavity is interconnected with the inner cavity of the first sealing cylinder, and the guide vane is fixedly installed inside the connecting pipe; the protective cylinder is fixedly installed on the outer wall of the housing, the second sealing cylinder is fixedly arranged inside the protective cylinder, the end of the connecting pipe extends into the inner cavity of the protective cylinder and is sealed and connected to the inner cavity of the second sealing cylinder, the second piston rod is laterally slidably and sealingly installed inside the second sealing cylinder, the flexible block is fixedly assembled on the outer end of the second piston rod near the transformer body, the first spring is assembled between the flexible block and the second piston rod, and the abutment block is fixedly installed on the inner wall of the housing.

[0006] In the above embodiment, the bottom surface of the transformer body presses down to contact the trigger pad, and the downward squeezing force is transmitted to the piston rod one, driving the piston rod one to slide vertically downward along the inside of the sealing cylinder one, squeezing the pressure-transmitting liquid in the bottom cavity of the sealing cylinder one, and the hydraulic pressure inside the sealed pipeline rises synchronously; when the liquid flows through the guide plate inside the connecting pipe, the guide plate diverts the instantaneous impact pressure of the buffer liquid, equalizes the pressure throughout the pipeline, and the equal pressure liquid is synchronously delivered to the inside of the sealing cylinder two on the left and right sides of the housing. The hydraulic thrust generated by the liquid overcomes the preset elastic tension of the first spring, pushing the piston rod two to slide laterally towards the transformer body, and the flexible block fixed at the end of the piston rod two synchronously adheres to and presses against the outer walls on both sides of the transformer body.

[0007] According to the above technical solution, the current transformer body is detachably installed in the internal cavity of the housing. The current transformer body is floated and a floating buffer gap is reserved between it and the inner wall of the housing. The interface is assembled on the side wall of the housing and is used to conduct and lead out the detection signal of the current transformer body.

[0008] According to the above technical solution, the protective cylinder, the second sealing cylinder, the second piston rod, the flexible block, and the first spring are mirrored at one point along the vertical central axis of the transformer body, so that the hydraulic transmission stroke and structural resistance on both sides are completely consistent, ensuring that the second piston rod on both sides slides synchronously. The abutment block is mirrored at one point along the transverse central axis of the transformer body.

[0009] According to the above technical solution, the trigger pad is made of flexible buffer material, and the guide plate is fixedly embedded in the middle section of the connecting pipe. The guide plate weakens the impact of the liquid and balances the hydraulic output pressure of the left and right pipes.

[0010] According to the above technical solution, the single-phase grounding fault detection combined instrument transformer also includes a docking mechanism and a protection mechanism; the docking mechanism is installed inside the housing to realize the rapid assembly and positioning of the instrument transformer, and after assembly, the whole is in a floating elastic support state, without generating rigid assembly stress; the protection mechanism is installed on the instrument transformer body to effectively shield and protect the outer wall of the instrument transformer, the wiring area, and the assembly gap.

[0011] According to the above technical solution, the docking mechanism includes a docking button and a docking groove; the docking button is detachably mounted on the bottom of the transformer body, and the docking groove is formed on the docking button.

[0012] According to the above technical solution, the docking mechanism further includes a second spring, a docking frame, a buffer sleeve, a release rod, a docking block, a third spring, and a cover. The second spring is fixedly arranged at the bottom side of the inner cavity of the housing. The docking frame is fixedly assembled on the top end face of the second spring. The buffer sleeve is assembled at the upper docking position of the docking frame. The release rod is slidably assembled vertically in the inner cavity of the docking frame. The docking block is fixedly installed on the release rod. The third spring is assembled between the docking block and the docking frame. The cover is rotatably assembled on the outer surface of the housing corresponding to the operating position of the release rod.

[0013] In the above embodiment, the current transformer body continues to slide downwards, and the bottom inclined surface of the bottom mating button contacts and presses against the upper inclined surface of the mating block. The downward assembly force pushes the mating block to slide laterally. During the lateral movement of the mating block, the No. 3 spring is continuously compressed, and the No. 3 spring stores elastic potential energy. As the current transformer body continues to descend, the mating groove opened inside the mating button is displaced to be precisely aligned with the lateral position of the mating block. The No. 3 spring releases the stored elastic reset force and pushes the mating block to slide laterally and reset, so that the mating block is laterally inserted into the mating groove.

[0014] According to the above technical solution, the docking mechanism further includes a guide block and a guide groove; the guide block is fixedly installed on the outer wall surface of the transformer body, and the guide groove is opened inside the inner wall of the housing.

[0015] According to the above technical solution, the protective mechanism includes a protective cover, an expansion cover, and a connecting piece; the protective cover is assembled and fixed to the outer side of the transformer body through the connecting piece, and the expansion cover is correspondingly assembled on the left and right sides of the protective cover to widen the lateral protection range of the protective cover and achieve full coverage protection of the side structure of the transformer body.

[0016] According to the above technical solution, the protective mechanism further includes a junction seat, a sealing cover, and a stress rod; the junction seat is fixedly installed on the outer wall of the protective cover, the sealing cover is rotatably assembled on the junction seat, and a torsion spring is installed between the rotating engagement position of the sealing cover and the junction seat. Under normal conditions, the torsion spring provides elastic restoring torque to the sealing cover, so that the sealing cover is normally kept in a closed blocking state. The stress rod is fixedly installed in the internal cavity of the sealing cover, and the rod structure of the stress rod matches the threaded structure of the connecting piece to form a threaded locking fit.

[0017] In the above embodiments, under normal operating conditions, the torsion springs arranged between the connector and the sealing cover continuously apply rotational torque to the sealing cover, driving the sealing cover to always maintain a closed state that fits against the protective cover, and the sealing cover completely covers the assembly gap between the connecting piece and the protective cover, as well as the screw position of the connecting piece.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In this invention, the transformer body is suspended without rigid fixation. Under normal conditions, floating gaps are maintained between the transformer body, the shell, and the vibration damping structure. This effectively avoids the internal casting stress caused by temperature expansion and contraction and equipment vibration in the traditional rigid fixing method of transformer body. It also avoids problems such as epoxy resin shell cracking, internal core displacement, and winding loosening. This structure relies on the transformer's own vibration displacement to trigger hydraulic transmission and achieve double-sided synchronous vibration damping. The greater the vibration, the stronger the hydraulic clamping force, which can effectively absorb the high-frequency and impact vibration generated during operation. There will be no problem of unilateral displacement or unilateral compression deformation. After the vibration disappears, the No. 1 spring can automatically reset and release pressure, allowing the flexible block to detach from the outer wall of the transformer and restore the suspension gap. It retains the thermal expansion and contraction deformation margin of the transformer body for a long time.

[0019] 2. In this invention, the sliding limit cooperation between the guide block and the guide groove ensures that the current transformer body can only be assembled vertically and precisely, eliminating assembly offset and misalignment, and ensuring precise alignment of the bottom docking structure. During the assembly process, the inclined surface pushes the docking block to retract and compress the No. 3 spring. After it is in place, the spring automatically resets and locks into the docking groove to achieve locking and fixation. No screws or complex fixing structures are required, which enables the current transformer body to be quickly assembled and positioned. After assembly, the whole body is in a floating elastic support state, without generating rigid assembly stress, which further adapts to the floating working requirements of the hydraulic vibration damping structure.

[0020] 3. In this invention, the protective cover is stably assembled to the outside of the transformer body via connecting pieces, forming a large-area, fully covered protective area with the expansion covers on both sides. This effectively shields and protects the outer wall of the transformer, the wiring area, and the assembly gaps, blocking outdoor rainwater, dust, oil, and sun erosion. It avoids insulation degradation, partial discharge, and signal drift caused by moisture and dirt accumulation on the casing, and stabilizes the sampling accuracy of single-phase grounding fault detection. The stress rod fixed inside the sealing cover can form a threaded locking fit with the threaded opening of the connecting piece after the sealing cover is closed, providing a secondary mechanical anti-loosening limit for the protective cover assembly structure. This effectively resists connection loosening caused by long-term outdoor vibration and temperature difference deformation, preventing the protective cover from becoming loose, shifting, or falling off and failing. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure at the positions of the protective cylinder and the shield cover of the present invention; Figure 3 This is a schematic diagram of the structure at the positions of the contact block and the guide groove of the present invention; Figure 4 This is a schematic diagram of the structure of the flexible block and the sealing cylinder at one location according to the present invention; Figure 5 For the present invention Figure 4 Enlarged schematic diagram of section A of the structure; Figure 6 This is a schematic diagram of the structure at the location of the docking button and the docking bracket of the present invention; Figure 7 This is a schematic diagram of the structure at the locations of the protective cover and the transformer body of the present invention; Figure 8 For the present invention Figure 7 An enlarged schematic diagram of the structure of part B in the middle section.

[0022] The labels in the diagram represent the following: 1. Housing; 2. Current transformer body; 3. Interface; 4. Sealing cylinder one; 5. Piston rod one; 51. Trigger pad; 6. Connecting pipe; 7. Guide plate; 8. Protective cylinder; 9. Sealing cylinder two; 10. Piston rod two; 11. Flexible block; 12. Spring one; 13. Contact block; 20. Docking button; 21. Docking groove; 22. Spring two; 23. Docking frame; 24. Buffer sleeve; 25. Release rod; 26. Docking block; 27. Spring three; 28. Cover; 29. ​​Guide block; 210. Guide groove; 30. Protective cover; 31. Expansion cover; 32. Connecting piece; 33. Interchange seat; 34. Sealing cover; 35. Stress rod. Detailed Implementation

[0023] Example 1: Please see Figures 1-8One embodiment of the present invention is: a combined current transformer for single-phase grounding fault detection, comprising a housing 1, a current transformer body 2, an interface 3, and a mitigation mechanism; the mitigation mechanism includes a sealing cylinder 4, a piston rod 5, a trigger pad 51, a connecting pipe 6, a guide vane 7, a protective cylinder 8, a second sealing cylinder 9, a second piston rod 10, a flexible block 11, a first spring 12, and a contact block 13; the sealing cylinder 4 is fixedly assembled inside the housing 1, the piston rod 5 is vertically slidably and sealingly installed inside the sealing cylinder 4, the trigger pad 51 is fixedly assembled at the top end of the piston rod 5, and the connecting pipe 6 is fixedly arranged inside the housing 1, the inside of the connecting pipe 6 being sealed and filled with a pressure-transmitting liquid. One end of the connecting pipe 6 is connected to the inner cavity of the sealing cylinder 4. The guide plate 7 is fixedly installed inside the connecting pipe 6. The protective cylinder 8 is fixedly installed on the outer wall of the housing 1. The sealing cylinder 9 is fixedly arranged inside the protective cylinder 8. The end of the connecting pipe 6 extends into the protective cylinder 8 and is sealed and connected to the inner cavity of the sealing cylinder 9. The piston rod 10 is laterally slidably and sealed inside the sealing cylinder 9. The flexible block 11 is fixedly assembled on the outer end of the piston rod 10 near the transformer body 2. The first spring 12 is assembled between the flexible block 11 and the piston rod 10. The contact block 13 is fixedly installed on the inner wall of the housing 1.

[0024] In the above embodiment, the abutment block 13 and the flexible block 11 have the same characteristics. The abutment block 13 is fixedly installed on the front and rear sides of the transformer body 2, respectively, and is in conventional vibration reduction protection, while the flexible blocks 11 on both sides are dynamically adaptive to achieve the protection effect.

[0025] The transformer body 2 is detachably installed in the internal cavity of the housing 1. The transformer body 2 is floated and a floating buffer gap is reserved between it and the inner wall of the housing 1. The interface 3 is assembled on the side wall of the housing 1 and is used to conduct and lead out the detection signal of the transformer body 2.

[0026] The protective cylinder 8, the sealing cylinder 2 9, the piston rod 2 10, the flexible block 11, and the first spring 12 are mirrored along the vertical central axis of the transformer body 2, so that the hydraulic transmission stroke and structural resistance on both sides are completely consistent, ensuring that the piston rods 2 10 on both sides slide synchronously. The contact block 13 is mirrored along the transverse central axis of the transformer body 2.

[0027] The trigger pad 51 is made of flexible buffer material, and the guide plate 7 is fixedly embedded in the middle section of the connecting pipe 6. The guide plate 7 weakens the impact of the liquid and balances the hydraulic output pressure of the left and right pipes.

[0028] In the above embodiments, dual-sided synchronous adaptive vibration reduction is achieved. The greater the vibration impact intensity, the greater the downward stroke of the transformer body 2, the higher the hydraulic pressure inside the pipeline, and the synchronous increase of the clamping and squeezing force of the flexible block 11 on the transformer body 2, thus forming an adaptive damping adjustment effect for vibration intensity.

[0029] The single-phase grounding fault detection combined instrument transformer also includes a docking mechanism and a protection mechanism; the docking mechanism is installed inside the housing 1 to realize the rapid assembly and positioning of the instrument transformer, and after assembly, the whole is in a floating elastic support state, without generating rigid assembly stress; the protection mechanism is installed on the instrument transformer body 2 to effectively shield and protect the outer wall of the instrument transformer, the wiring area, and the assembly gap.

[0030] In this embodiment, the entire system uses the housing 1 as the supporting base. The current transformer body 2 is detachably floating inside the housing 1. An initial gap is maintained between the bottom surface of the current transformer body 2 and the trigger pad 51 fixed to the top of the piston rod 5. The sealing cylinder 4, the connecting pipe 6, and the two sealing cylinders 9 on both sides are interconnected to form a complete sealed cavity. The cavity is filled with pressure-transmitting liquid. A guide plate 7 is fixed inside the connecting pipe 6. Protective cylinders 8 are symmetrically arranged on the left and right outer sides of the housing 1 to wrap the sealing cylinder 9, piston rod 10, flexible block 11, and spring 12. Under normal operating conditions, spring 12 continuously applies an outward elastic force to piston rod 10, causing piston rod 10 to retract towards sealing cylinder 9. 11. The transformer body 2 is located away from the left and right side walls. The transformer body 2 retains a complete floating buffer gap around its perimeter, free from rigid constraints by external structures. When the outdoor switch connected to the transformer vibrates and impacts during opening and closing, the vibration load causes the transformer body 2 to undergo a downward vertical displacement. The bottom surface of the transformer body 2 presses down onto the trigger pad 51, transmitting the downward pressure to the piston rod 5. This causes the piston rod 5 to slide vertically downwards along the inside of the sealing cylinder 4, compressing the pressure-transmitting liquid in the bottom cavity of the sealing cylinder 4. The hydraulic pressure inside the sealed pipeline rises synchronously. When the liquid flows through the guide vane 7 inside the connecting pipe 6, the guide vane 7 diverts the instantaneous impact pressure of the buffer liquid, balancing the pressure throughout the pipeline. The pressurized liquid is synchronously delivered to the interior of the sealing cylinders 9 on both sides of the housing 1. The hydraulic thrust generated by the liquid overcomes the preset elastic tension of the first spring 12, pushing the piston rod 10 to slide laterally towards the transformer body 2. The flexible block 11 fixed at the end of the piston rod 10 synchronously adheres to and presses against the outer walls on both sides of the transformer body 2. Relying on the elastic deformation of the contact block 13 and the flexible block 11, the vibration impact energy is absorbed and dissipated, realizing synchronous adaptive vibration reduction on both sides. The greater the vibration impact intensity, the greater the downward stroke of the transformer body 2, and the higher the hydraulic pressure inside the pipeline. The clamping and squeezing force of the flexible block 11 on the transformer body 2 increases synchronously, forming an adaptive damping adjustment effect of vibration intensity. When the external After the vibration and impact completely disappear, the transformer body 2 rebounds upward and separates from the trigger pad 51. The interior of the sealing cylinder 4 is no longer squeezed downward, and the overall hydraulic pressure of the pipeline drops synchronously. The first spring 12 on both sides releases the pre-stretched elastic potential energy, pulling the piston rod 10 to slide outward and push the pressure-transmitting liquid inside the sealing cylinder 9 back into the cavity of the sealing cylinder 4. The flexible block 11 separates from the side wall of the transformer body 2 again, restoring the floating buffer gap required for the floating installation of the transformer body 2, reserving the deformation margin required for the thermal expansion and contraction of the transformer body 2, ensuring the long-term symmetrical arrangement of the PT and CT cores inside the transformer, and stabilizing the accuracy of zero-sequence voltage and zero-sequence current acquisition.

[0031] Example 2: Please see Figures 1-8Based on the above embodiments, in another embodiment of the present invention, the docking mechanism includes a docking button 20 and a docking groove 21; the docking button 20 is detachably mounted on the bottom of the transformer body 2, and the docking groove 21 is formed on the docking button 20.

[0032] The docking mechanism also includes a second spring 22, a docking frame 23, a buffer sleeve 24, a release rod 25, a docking block 26, a third spring 27, and a cover 28. The second spring 22 is fixedly arranged at the bottom of the inner cavity of the housing 1. The docking frame 23 is fixedly assembled on the top end face of the second spring 22. The buffer sleeve 24 is assembled at the upper docking position of the docking frame 23. The release rod 25 is slidably assembled vertically in the inner cavity of the docking frame 23. The docking block 26 is fixedly installed on the release rod 25. The third spring 27 is assembled between the docking block 26 and the docking frame 23. The cover 28 is rotatably assembled on the outer surface of the housing 1 corresponding to the operating position of the release rod 25.

[0033] The docking mechanism also includes a guide block 29 and a guide groove 210; the guide block 29 is fixedly installed on the outer wall surface of the transformer body 2, and the guide groove 210 is opened inside the inner wall of the housing 1.

[0034] In the above embodiment, during the assembly process, the inclined surface presses against the driving docking block 26 to retract and compress the No. 3 spring 27. After it is in place, the spring automatically resets and snaps into the docking groove 21 to achieve locking and fixation. No screws are needed for tightening or complex fixing structures are required, thus achieving rapid assembly and positioning of the current transformer body 2.

[0035] In this embodiment, the following steps are taken: The current transformer body 2 is attached to the housing 1, the transformer body 2, and the bottom locking assembly to complete the floating assembly and disassembly of the current transformer body 2. A guide block 29 is fixed to the outside of the current transformer body 2. A guide groove 210 matching the guide block 29 is opened on the inner wall of the housing 1. A docking button 20 is installed at the bottom of the current transformer body 2, and a docking groove 21 is opened inside the docking button 20. A second spring 22 is arranged on the bottom side of the inner cavity of the housing 1. A docking frame 23 is fixed to the top of the second spring 22. A buffer sleeve 24 is installed on the upper end of the docking frame 23. A release rod 25 is vertically slidably installed inside the docking frame 23. A docking block 26 is fixed to the top of the release rod 25. A third spring 2 is installed between the docking block 26 and the inner wall of the docking frame 23. 7. A cover 28 is rotatably installed on the surface of housing 1. Under normal conditions, the cover 28 completely covers the exposed operating end of the release rod 25. When the current transformer body 2 is assembled and fixed in the air, the guide block 29 on the outside of the current transformer body 2 is aligned with the guide groove 210 on the inner wall of housing 1. The sliding limit cooperation between the guide block 29 and the guide groove 210 restricts the current transformer body 2 to move only vertically downward, avoiding left and right offset during assembly. As the current transformer body 2 continues to slide downward, the bottom inclined surface of the bottom mating button 20 contacts and presses against the upper inclined surface of the mating block 26. The downward assembly force pushes the mating block 26 to slide laterally. During the lateral movement of the mating block 26, it is continuously compressed. Spring 27, the third spring, stores elastic potential energy. As the transformer body 2 continues to descend, the docking groove 21 inside the docking button 20 shifts to precisely align with the lateral position of the docking block 26. Spring 27 releases the stored elastic restoring force, pushing the docking block 26 to slide laterally and reset, causing the docking block 26 to laterally engage with the docking groove 21. The engagement and limiting structure between the docking block 26 and the docking groove 21 completes the vertical locking of the transformer body 2. Spring 22 continues to support the docking frame 23, the docking button 20, and the transformer body 2 upwards, keeping the transformer body 2 in a floating installation state without rigid support. During assembly, the bottom of the docking button 20... The buffer sleeve 24 between the current transformer body 23 and the docking frame continuously buffers the impact force of hard contact, avoiding rigid collision and wear structure. When it is necessary to disassemble the current transformer body 2, manually rotate the cover 28 on the surface of the housing 1 to release the cover 28 from the protection of the release rod 25. Pull the release rod 25 outward, and the release rod 25 will simultaneously drive the docking block 26 to slide laterally, so that the docking block 26 is disengaged from the docking groove 21, and the locking relationship between the docking block 26 and the docking groove 21 is released. Lift the current transformer body 2 upward to complete the overall disassembly. After the disassembly is completed, release the release rod 25, and the cover 28 will rotate back to close and cover the release rod 25 again to prevent accidental unlocking during equipment operation.

[0036] Example 3: Please see Figures 1-8Based on the above embodiments, in another embodiment of the present invention, the protective mechanism includes a protective cover 30, an expansion cover 31, and a connecting piece 32; the protective cover 30 is assembled and fixed to the outer side of the transformer body 2 through the connecting piece 32, and the expansion cover 31 is correspondingly assembled to the left and right sides of the protective cover 30 to widen the lateral protection range of the protective cover 30 and achieve full coverage protection of the side structure of the transformer body 2.

[0037] The protective mechanism also includes a junction seat 33, a sealing cover 34, and a stress rod 35. The junction seat 33 is fixedly installed on the outer wall of the protective cover 30. The sealing cover 34 is rotatably mounted on the junction seat 33. A torsion spring is installed between the rotating engagement position of the sealing cover 34 and the junction seat 33. Under normal conditions, the torsion spring provides elastic restoring torque to the sealing cover 34, so that the sealing cover 34 is normally kept in a closed blocking state. The stress rod 35 is fixedly installed in the internal cavity of the sealing cover 34. The rod structure of the stress rod 35 matches the threaded structure of the connecting piece 32 and forms a threaded locking fit.

[0038] In the above embodiments, the side walls and outer assembly gaps of the current transformer body are fully covered to prevent outdoor rainwater, dust and sun exposure from directly eroding the outer wall of the current transformer and to avoid moisture and dirt intrusion that could cause insulation degradation and sampling signal drift.

[0039] In this embodiment, the transformer body 2 serves as the assembly carrier. A protective cover 30 is fixedly mounted to the outside of the transformer body 2 via a connecting piece 32. Expansion covers 31 are mounted on the left and right sides of the protective cover 30, respectively. A junction seat 33 is fixed to the outer wall of the protective cover 30. A sealing cover 34 is rotatably mounted on the junction seat 33. A torsion spring is installed between the junction seat 33 and the sealing cover 34 at their hinged positions. A stress rod 35 is fixed inside the cavity of the sealing cover 34. The structure of the stress rod 35 matches the threaded opening of the connecting piece 32. Under normal operating conditions, the torsion spring between the junction seat 33 and the sealing cover 34 continuously applies rotational torque to the sealing cover 34, driving it to remain in a closed state, always fitting against the protective cover 30. The sealing cover 34 completely covers the connecting piece 32 and the protective cover 30. When the sealing cover 34 is closed, the stress rod 35 fixed inside the sealing cover 34 rotates synchronously with the sealing cover 34, and the stress rod 35 is screwed into the thread of the connecting piece 32. The stress rod 35 and the thread of the connecting piece 32 are engaged to form a secondary locking and limiting structure, which counteracts the tendency of the connecting piece 32 to loosen due to long-term outdoor vibration and temperature difference deformation, and prevents the assembly of the protective cover 30 and the transformer body 2 from loosening. The protective cover 30, together with the two side expansion covers 31, forms a large-area overall shielding structure, which fully covers and shields the side wall and outer assembly gap of the transformer body 2, preventing outdoor rainwater, dust and sun exposure from directly eroding the outer wall of the transformer, and avoiding the intrusion of water vapor and dirt that cause insulation degradation and sampling signal drift.

Claims

1. A combined instrument transformer for single-phase ground fault detection, characterized in that, It includes a housing (1), a transformer body (2), an interface (3), and a damping mechanism; The deceleration mechanism includes a sealing cylinder (4), a piston rod (5), a trigger pad (51), a connecting pipe (6), a guide plate (7), a protective cylinder (8), a sealing cylinder (9), a piston rod (10), a flexible block (11), a spring (12), and a contact block (13). The sealing cylinder (4) is fixedly assembled inside the housing (1), the piston rod (5) is vertically slidably sealed inside the sealing cylinder (4), the trigger pad (51) is fixedly assembled at the top of the piston rod (5), the connecting pipe (6) is fixedly arranged inside the housing (1), the connecting pipe (6) is sealed and filled with pressure-transmitting liquid, one end of the connecting pipe (6) is connected to the internal cavity of the sealing cylinder (4), and the guide plate (7) is fixedly installed inside the connecting pipe (6). The protective cylinder (8) is fixedly installed on the outer wall of the housing (1), the sealing cylinder two (9) is fixedly arranged inside the protective cylinder (8), the connecting pipe (6) extends into the end of the pipe inside the protective cylinder (8) and is sealed and connected to the internal cavity of the sealing cylinder two (9), the piston rod two (10) is laterally slidably and sealed inside the sealing cylinder two (9), the flexible block (11) is fixedly assembled on the outer end of the piston rod two (10) near the transformer body (2), the first spring (12) is assembled between the flexible block (11) and the piston rod two (10), and the abutment block (13) is fixedly installed on the inner wall of the housing (1); The transformer body (2) is detachably installed in the internal cavity of the housing (1). The transformer body (2) is floated and has a floating buffer gap reserved with the inner wall of the housing (1). The interface (3) is assembled on the side wall of the housing (1) for conducting and leading out the detection signal of the transformer body (2). The abutment block (13) has the same characteristics as the flexible block (11). There are two abutment blocks (13), and the two abutment blocks (13) are fixedly installed on the front and rear sides of the transformer body (2) to protect the front and rear sides of the transformer body (2). The number of the guide plate (7), protective cylinder (8), sealing cylinder II (9), piston rod II (10), flexible block (11) and spring No. 1 (12) are all set in two, and are arranged symmetrically to each other, so that the hydraulic transmission stroke and structural resistance on both sides are completely consistent, ensuring that the piston rod II (10) on both sides slides synchronously. The trigger pad (51) is made of flexible buffer material. The guide plate (7) is fixedly embedded in the middle section of the connecting pipe (6). The guide plate (7) weakens the impact of the liquid and balances the hydraulic output pressure of the two pipes.

2. The combined instrument transformer for single-phase ground fault detection according to claim 1, characterized in that: The single-phase grounding fault detection combined instrument transformer also includes a docking mechanism and a protection mechanism; The docking mechanism is installed inside the housing (1) to realize convenient assembly and positioning of the mutual inductor. After assembly, the whole is in a floating elastic support state and does not generate rigid assembly stress. The protective mechanism is installed on the transformer body (2) to effectively shield and protect the outer wall of the transformer, the wiring area and the assembly gap.

3. The combined instrument transformer for single-phase ground fault detection according to claim 2, characterized in that: The docking mechanism includes a docking button (20) and a docking groove (21); The docking button (20) is detachably mounted on the bottom of the transformer body (2), and the docking groove (21) is formed on the docking button (20).

4. The combined instrument transformer for single-phase ground fault detection according to claim 3, characterized in that: The docking mechanism also includes a second spring (22), a docking frame (23), a buffer sleeve (24), a release rod (25), a docking block (26), a third spring (27), and a cover (28); The second spring (22) is fixedly arranged at the bottom of the inner cavity of the housing (1). The docking frame (23) is fixedly assembled on the top end face of the second spring (22). The buffer sleeve (24) is assembled at the upper docking position of the docking frame (23). The release rod (25) is slidably assembled in the inner cavity of the docking frame (23) along the vertical direction. The docking block (26) is fixedly installed on the release rod (25). The third spring (27) is assembled between the docking block (26) and the docking frame (23). The cover (28) is rotatably assembled on the outer surface of the housing (1) corresponding to the operating position of the release rod (25).

5. The combined instrument transformer for single-phase ground fault detection according to claim 4, characterized in that: The docking mechanism also includes a guide block (29) and a guide groove (210); The guide block (29) is fixedly installed on the outer wall surface of the transformer body (2), and the guide groove (210) is opened inside the inner wall of the housing (1).

6. The combined instrument transformer for single-phase ground fault detection according to claim 2, characterized in that: The protective mechanism includes a protective cover (30), an expansion cover (31), and a connecting piece (32). The protective cover (30) is assembled and fixed to the outer side of the transformer body (2) via the connecting piece (32). The expansion cover (31) is assembled on both sides of the protective cover (30) to widen the lateral protection range of the protective cover (30) and achieve full coverage protection of the side structure of the transformer body (2).

7. The combined instrument transformer for single-phase ground fault detection according to claim 6, characterized in that: The protective mechanism also includes a junction seat (33), a sealing cover (34), and a stress rod (35). The junction seat (33) is fixedly installed on the outer wall of the protective cover (30). The sealing cover (34) is rotatably assembled on the junction seat (33). A torsion spring is installed between the rotating engagement position of the sealing cover (34) and the junction seat (33). The torsion spring provides elastic restoring torque to the sealing cover (34) under normal conditions, so that the sealing cover (34) is normally kept in a closed blocking state. The stress rod (35) is fixedly installed in the internal cavity of the sealing cover (34). The rod structure of the stress rod (35) matches the threaded structure of the connecting piece (32) and forms a threaded locking fit.

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