A miniaturized cable testing device for ring main units

Abstract

The application provides a miniaturized cable testing device for a ring net cabinet, and relates to the technical field of cable testing. The miniaturized cable testing device for the ring net cabinet comprises a cable and a testing host. Three T-shaped cable joints are arranged above the cable, and three phase lines of the cable are respectively fixedly connected with adjacent T-shaped cable joints. One port of each of the three T-shaped cable joints is fixedly connected with a detection joint assembly. The outer surface of each of the three detection joint assemblies is fixedly sleeved with a coupling detection assembly. Through the integrated design of the coupling detection assembly and the detection joint assembly, the cable is continuously screened online by the coupling detection assembly in the live operating state, and the detection joint assembly performs active pulse diagnosis during power-off maintenance. One set of device realizes full-process coverage from abnormal early warning to accurate positioning of defects, without the need of replacing or switching equipment, and significantly improves the operation and maintenance efficiency.

Description

Technical Field

[0001] This invention relates to the field of cable testing technology, specifically to a miniaturized cable testing device for ring main units. Background Technology

[0002] As a critical node device in the power distribution network, the insulation condition of the outgoing cables of the ring main unit directly affects the reliability of power supply. During long-term operation, cross-linked polyethylene insulated power cables can develop insulation defects such as water trees and partial discharge due to factors such as electrical aging, thermal aging, moisture absorption, and mechanical damage. If these defects are not detected and addressed promptly, they may develop into permanent grounding faults, leading to line tripping and power outages for users. Therefore, regularly conducting insulation tests on the outgoing cables of the ring main unit is a crucial aspect of power distribution network operation and maintenance.

[0003] Currently, insulation testing of outgoing cables in ring main units faces the following problems: Firstly, conventional cable insulation testing requires taking the cable out of operation, removing the T-type cable joints, and using an independent insulation resistance tester or dielectric loss tester for offline testing. This process is cumbersome, time-consuming, and frequent disassembly and reassembly of T-type cable joints accelerates the degradation of the insulation interface. While some online monitoring devices can perform uninterrupted testing, most passively pick up signals through capacitive coupling, allowing only screening-level detection such as partial discharge. They cannot quantitatively assess the insulation resistance of cables under active high-voltage excitation or accurately locate defects, resulting in limited detection depth. Secondly, existing technologies lack devices that effectively integrate online screening with offline active diagnosis. Maintenance personnel find it difficult to perform the entire process from anomaly warning to accurate location on a single system, often requiring multiple independent devices to complete the task step by step, leading to low maintenance efficiency and difficulty in data correlation and comparison.

[0004] To address this, we have developed a new miniaturized cable testing device for ring main units. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a miniaturized cable testing device for ring main units, which solves the problems of low efficiency in offline testing and shallow depth in online monitoring of insulation testing of outgoing cables in existing ring main units, as well as the disconnect between the two and the inability to work together in an integrated manner.

[0006] (II) Technical Solution To achieve the above objectives, the present invention is implemented through the following technical solution: a miniaturized cable testing device for ring main units, comprising a cable and a testing host, wherein three T-type cable connectors are provided above the cable, and the three phase wires of the cable are respectively fixedly plugged into the adjacent T-type cable connectors; Each of the three T-type cable connectors has a detection connector assembly fixedly inserted into one of its ports; The outer surfaces of the three detection connector assemblies are all fixedly sleeved with coupling detection components, and the three coupling detection components are all electrically connected to the test host via a first cable; One end of each of the three detection connector assemblies is fixedly connected to a main cylinder, and a differential pressure compensation assembly is fixedly connected to one side of the top of each of the three main cylinders. The inner surfaces of the three main cylinders are all fixedly connected with inner cylinders, and the outlets of the three inner cylinders are all hinged with closing plates. All three closing plates and the main cylinders are connected together with an elastic reset assembly. The inner surfaces of the three inner cylinders are all slidably connected with piston rings, and the inner surfaces of the three piston rings are all fixedly connected with long rods. The three long rods are all provided with grooves at one end of the closing plate, and the three grooves are all equipped with elastic contacts, which are matched with the detection connector assembly. The other ends of the three long rods are fixedly connected to a quick reset assembly. One end of the quick reset assembly is equipped with three second cables, and the second cables are electrically connected to the adjacent elastic contacts and the test host. The outer surfaces of the three main cylinders are all fixedly fitted with a support steel frame. One side of the outer surface of the support steel frame is fixedly connected with an elastic buckle, and the elastic buckle matches the quick reset assembly.

[0007] Preferably, all three of the test connector assemblies include an insulating jacket, and the insulating jacket is fixedly inserted into the adjacent port of the T-type cable connector. A copper rod is fixedly connected to the inner surface of the insulating jacket, and the copper rod is in close contact with the internal copper core of the adjacent port of the T-type cable connector.

[0008] Through the above technical solution, the copper rod and the internal copper core are tightly connected to ensure the stability of the electrical path, and the insulating jacket provides insulation protection to the ground.

[0009] Preferably, all three coupling detection components include an insulating ring, which is fixedly embedded in the outer surface of the insulating jacket. A detection ring is provided on the inner side of the insulating ring, and a metal shielding ring is fixedly sleeved on the outer surface of the insulating ring. A grounding plate is fixedly connected to the bottom of the metal shielding ring.

[0010] Through the above technical solution, the detection ring forms a stable coupling capacitance between the insulating ring and the insulating jacket to pick up high-frequency signals inside the cable, and the metal shielding ring is reliably grounded through the grounding plate, effectively shielding against external electromagnetic interference.

[0011] Preferably, each of the three first cables is fixedly connected to a first plug at its bottom, the bottom of the first plug is inserted into a first socket, and the first socket is fixedly connected to the insulating jacket and electrically connected to the adjacent detection ring.

[0012] With the above technical solution, the first cable is connected to the coupling detection component by a plug-in method, which facilitates installation, disassembly and maintenance.

[0013] Preferably, all three differential pressure compensation components include a fixed cylinder, and the fixed cylinder is fixedly connected to the top of the main cylinder. The inner surface of the fixed cylinder is slidably connected to a piston plate, and the top of the fixed cylinder has a through hole extending into the interior.

[0014] With the above technical solution, when the piston ring moves and causes the internal pressure of the inner cylinder to change, the insulating medium can push the piston plate to slide up and down in the fixed cylinder. The through hole keeps the upper part of the fixed cylinder connected to the external atmosphere, so that the piston plate can freely respond to pressure changes and realize the automatic balance of the internal pressure of the inner cylinder.

[0015] Preferably, each of the three elastic contacts includes a first compression spring, and the first compression spring is fixedly connected to the inner wall of one side of the groove. One end of the first compression spring is fixedly connected to a slider, and the slider is slidably connected to the inner wall of the groove in a sealed manner. One end of the slider is fixedly embedded with a copper contact.

[0016] With the above technical solution, when the copper contact comes into contact with the copper rod, the first compression spring is compressed to provide cushioning and avoid rigid collision. After contact, the continuous elastic force of the first compression spring keeps the copper contact and the copper rod in a stable elastic contact, ensuring the reliability of the electrical connection during diagnostic testing.

[0017] Preferably, all three elastic reset components include a housing, and the housings are fixedly connected to the top of the main cylinder. A sliding plate is slidably connected to the inner surface of the housing. Two second compression springs are fixedly connected to the top of the sliding plate and the inner top wall of the housing. A sloped pressure rod is fixedly connected to the bottom of the sliding plate, and the sloped surface of the sloped pressure rod slides against the sloped surface of the closing plate.

[0018] With the above technical solution, when the closing plate is pushed open, the inclined pressure rod rises along the inclined surface of the closing plate and compresses the second compression spring. When the long rod is withdrawn, the second compression spring releases its elastic force to push the inclined pressure rod downward. The inclined pressure rod drives the closing plate to quickly reset and close through the inclined surface cooperation, ensuring the timeliness and reliability of the isolation action.

[0019] Preferably, the quick reset assembly includes three third compression springs, and the third compression springs are fixedly connected to one end of the inner cylinder and sleeved on the outer surface of the long rod. The three third compression springs and one end of the long rod are jointly fixedly connected to a horizontal plate, and a handrail is fixedly connected to one side of the outer surface of the horizontal plate.

[0020] Using the above technical solution, after the test is completed, the elastic buckle is released, and the three third compression springs release their elastic force simultaneously, pushing the horizontal plate to drive the three long rods to exit quickly as a whole.

[0021] Preferably, each of the three second cables has a second plug fixedly connected to its bottom. One end of the second plug is inserted into a second socket, which is fixedly connected to the horizontal plate and electrically connected to the copper contact. The outer surfaces of the three first cables and the two second cables are jointly fitted with a cable tray, which is fixedly connected to the test host.

[0022] Through the above technical solution, the second cable is connected to the second socket on the horizontal plate by plugging, which facilitates disassembly and maintenance. The cable tray neatly fixes the first and second cables, avoiding cable tangling and improving the cleanliness and reliability of the internal wiring of the device.

[0023] Preferably, the elastic buckle includes a mounting plate, which is fixedly connected to the supporting steel frame. Two tension springs are symmetrically fixedly connected to the bottom of the mounting plate, and a movable frame is fixedly connected to the bottom of the two tension springs. Two inclined blocks are symmetrically fixedly connected to the top of the movable frame, and the inclined blocks penetrate the mounting plate and are slidably connected to the mounting plate. A handle is fixedly connected to one side of the bottom of the movable frame.

[0024] With the above technical solution, when the horizontal plate is pushed into place, the inclined block automatically resets under the action of the tension spring to limit the horizontal plate. The operator only needs to pull down the handle to release the lock. The structure is simple and the operation is convenient.

[0025] (III) Beneficial Effects This invention provides a miniaturized cable testing device for ring main units. It has the following advantages: This miniaturized cable testing device for ring main units integrates a coupling detection component and a detection connector component. The coupling detection component continuously screens the cable online while it is in operation with power on, and the detection connector component performs active pulse diagnosis during power outage maintenance. One device achieves full-process coverage from abnormal early warning to accurate defect location without the need to replace or transfer equipment, which significantly improves operation and maintenance efficiency. This miniaturized cable testing device for ring main units, through the interconnection design between the differential pressure compensation component and the main cylinder, allows the internal insulating medium to enter the differential pressure compensation component or flow back from it when the long rod moves the piston ring. This automatically balances the pressure difference caused by volume changes inside the inner cylinder, avoiding increased resistance or jamming of the long rod movement due to excessive or insufficient pressure in the sealed cavity, thus ensuring smooth testing operations. This miniaturized cable testing device for ring main units, through the coordinated operation of a quick reset component and a closing plate, allows the long rod to quickly retract after testing, causing the copper contacts to separate rapidly from the copper rod. Simultaneously, the closing plate, driven by the elastic reset component, quickly closes the inner cylinder outlet, isolating the copper contacts from the copper rod. This shortens the arcing time during the separation process and avoids the continuous burning of the contact and electrode surfaces by residual arcs, ensuring the long-term contact reliability of the test connector assembly.

[0026] This miniaturized cable testing device for ring main units uses the elastic compression of the first compression spring in the elastic contact with the copper contact to buffer the copper contact with the copper rod instead of a rigid collision, thus avoiding damage to the contact surface from the insertion impact. At the same time, the continuous clamping force provided by the spring ensures the stability of the electrical contact during the test. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall first-view structure of the present invention; Figure 2 This is a schematic diagram of the overall second-view structure of the present invention; Figure 3 This is a top view of the overall structure of the present invention; Figure 4 for Figure 1 Enlarged view of point A in the middle; Figure 5 for Figure 1 Enlarged view of point B in the middle; Figure 6 This is a three-dimensional structural diagram of the elastic buckle of the present invention; Figure 7 This is a partial three-dimensional structural diagram of the present invention; Figure 8 This is a partial cross-sectional three-dimensional structural schematic diagram of the present invention; Figure 9 for Figure 8 Enlarged view of point C in the middle; Figure 10 for Figure 8 Enlarged view of point D in the middle.

[0028] The components are as follows: 1. Cable; 2. Supporting steel frame; 3. T-type cable connector; 4. Test host; 5. Cable tray; 6. First cable; 7. Second cable; 8. Handrail; 9. Handle; 10. Third compression spring; 11. Main cylinder; 12. Horizontal plate; 13. Insulating jacket; 14. Metal shielding ring; 15. Mounting plate; 16. First socket; 17. First plug; 18. Second plug; 19. Second socket; 20. Movable frame; 21. Inclined block; 22. Tension spring; 23. Grounding plate; 24. Fixed cylinder; 25. Housing; 26. Copper rod; 27. Long rod; 28. Piston ring; 29. ​​Piston plate; 30. Slider; 31. Groove; 32. First compression spring; 33. Inner cylinder; 34. Slide plate; 35. Second compression spring; 36. Closing plate; 37. Inclined pressure rod; 38. Copper contact; 39. Detection ring; 40. Insulating ring. Detailed Implementation

[0029] 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.

[0030] like Figure 1 , Figure 2As shown, this embodiment of the invention provides a miniaturized cable testing device for ring main units, including a cable 1 and a testing host 4. Three T-type cable connectors 3 are provided on the top of the cable 1, and the three phase wires of the cable 1 are respectively fixedly plugged into the adjacent T-type cable connectors 3. The testing host 4 integrates an online monitoring module, a diagnostic testing module, a mode switching module and a central processing unit. The online monitoring module includes a high-input-impedance broadband amplifier and a first high-speed analog-to-digital converter (ADC) for amplifying and digitizing the weak high-frequency signals picked up by the coupling detection component. The diagnostic test module includes a pulse generator, a high-voltage DC power supply, a second high-speed ADC, and a residual charge discharge circuit. The pulse generator generates a broadband pulse or a DC high-voltage diagnostic signal, which is injected into cable 1 through the diagnostic test channel. The second high-speed ADC collects the reflected echo signal. The residual charge discharge circuit safely discharges the residual charge on cable 1 after the diagnostic test is completed. The mode switching module is controlled by the central processing unit and automatically switches between online monitoring mode and diagnostic test mode according to the access status of the diagnostic test channel. When a contact confirmation signal is detected in the diagnostic test channel, it automatically switches from online monitoring mode to diagnostic test mode and closes the online monitoring channel. When the contact confirmation signal disappears and the discharge procedure is completed, it automatically switches back to online monitoring mode. The central processing unit includes a digital signal processor (DSP) and a microcontroller. The DSP executes partial discharge mode recognition, broadband admittance spectrum analysis, and time-domain reflectometry localization algorithms. The microcontroller controls mode switching, data storage, and external communication.

[0031] like Figure 3 , Figure 7 As shown, a detection connector assembly is fixedly inserted into one of the three T-type cable connectors 3. Each of the three detection connector assemblies includes an insulating jacket 13, and the insulating jacket 13 is fixedly inserted into the adjacent port of the T-type cable connector 3. The insulating jacket 13 is made of high-insulation-strength materials such as epoxy resin or silicone rubber, and its shape matches the port of the T-type cable connector 3. A copper rod 26 is fixedly connected to the inner surface of the insulating jacket 13. The copper rod 26 is made of copper with good conductivity. Its front end is tightly abutted against the internal copper core of the adjacent port of the T-type cable connector 3 to form a reliable electrical connection path, which is used to lead the signal of the high-voltage conductor inside the cable 1 to the subsequent detection structure.

[0032] like Figure 1 , Figure 3 , Figure 4 , Figure 7 , Figure 10As shown, each of the three detection connector assemblies has a coupling detection component fixedly sleeved on its outer surface. All three coupling detection components are electrically connected to the first cable 6 via the test host 4. Each coupling detection component includes an insulating ring 40, which is fixedly embedded in the outer surface of the insulating jacket 13. The insulating ring 40 is made of polytetrafluoroethylene or epoxy resin. A detection ring 39 is provided inside the insulating ring 40. The detection ring 39 is made of beryllium copper or pure copper and has a ring structure. A stable coupling capacitance is formed between the insulating ring 40 and the copper rod 26 inside the insulating jacket 13. When the cable 1 is energized, a high-frequency signal reflecting the insulation status of the cable 1 is picked up in a non-contact manner. A metal shielding ring 14 is fixedly fitted onto the surface, and a grounding plate 23 is fixedly connected to the bottom of the metal shielding ring 14. The metal shielding ring 14 is made of brass and is used to shield external electromagnetic interference. The grounding plate 23 is made of copper and is in reliable contact with the grounding metal partition of the ring network cabinet, so that the metal shielding ring 14 is reliably grounded. The bottom of each of the three first cables 6 is fixedly connected to a first plug 17. The bottom of the first plug 17 is plugged into a first socket 16, and the first socket 16 is fixedly connected to the insulating jacket 13 and electrically connected to the adjacent detection ring 39. The signal picked up by the detection ring 39 is transmitted to the test host 4 through the first socket 16, the first plug 17 and the first cable 6, and is monitored and analyzed online by the test host 4.

[0033] like Figure 8 As shown, one end of each of the three detection connector assemblies is fixedly connected to a main cylinder 11. The main cylinder 11 is hollow inside to form a sealed cavity, which is filled with an insulating medium, such as dry nitrogen. A differential pressure compensation assembly is fixedly connected to one side of the top of each of the three main cylinders 11. Each of the three differential pressure compensation assemblies includes a fixed cylinder 24, and the fixed cylinder 24 is fixedly connected to the top of the main cylinder 11. A piston plate 29 is slidably connected to the inner surface of the fixed cylinder 24. A through hole is opened at the top of the fixed cylinder 24 to the interior. A sealing ring is fitted on the piston plate 29 to form a sealed sliding fit with the inner wall of the fixed cylinder 24.

[0034] like Figure 7 , Figure 8 , Figure 9As shown, inner cylinders 33 are fixedly connected to the inner surfaces of the three main cylinders 11. Closing plates 36 are hinged to the outlets of the three inner cylinders 33. The closing plates 36 are made of insulating material and are installed on the outlet end face of the inner cylinders 33 through hinge shafts. Elastic reset components are installed together between the three closing plates 36 and the main cylinders 11. Each of the three elastic reset components includes a housing 25, and the housing 25 is fixedly connected to the top of the main cylinder 11. A sliding plate 34 is slidably connected to the inner surface of the housing 25. Two second compression springs 35 are fixedly connected to the top of the sliding plate 34 and the inner top wall of the housing 25. An inclined pressure rod 37 is fixedly connected to the bottom of the sliding plate 34, and the inclined surface of the inclined pressure rod 37 slides against the inclined surface of the closing plate 36. The second compression springs 35 are made of stainless steel spring wire and are used to provide the driving force for the closing plate 36 to reset.

[0035] like Figure 8 , Figure 9 As shown, piston rings 28 are slidably connected to the inner surfaces of the three inner cylinders 33. Long rods 27 are fixedly connected to the inner surfaces of the three piston rings 28. Grooves 31 are provided at one end of the three long rods 27 located on the closing plate 36. Elastic contacts are installed in the three grooves 31 and are matched with the detection connector assembly. Each elastic contact includes a first compression spring 32, which is fixedly connected to the inner wall of one side of the groove 31. The first compression spring 32 is made of stainless steel spring wire. A slider 30 is fixedly connected to one end of the first compression spring 32 and is slidably connected to the inner wall of the groove 31. A sealing ring is fitted on the outer surface of the slider 30. A copper contact 38 is fixedly embedded at one end of the slider 30. The copper contact 38 is made of copper or silver-copper alloy and has a smooth front surface for forming reliable electrical contact with the end face of the copper rod 26.

[0036] like Figure 1 , Figure 7 As shown, the other ends of the three long rods 27 are all fixedly connected to a quick reset assembly. The quick reset assembly includes three third compression springs 10, which are made of stainless steel spring wire. They are fixedly connected to one end of the inner cylinder 33 and sleeved on the outer surface of the long rods 27. The three third compression springs 10 and one end of the three long rods 27 are all fixedly connected to a horizontal plate 12. The horizontal plate 12 is made of metal or high-strength insulating board and is used to connect the three long rods 27 into one piece. A handrail 8 is fixedly connected to one side of the outer surface of the horizontal plate 12. The outer surface of the handrail 8 is provided with anti-slip texture, which makes it easy for the operator to hold and push and pull. When the test is completed and the lock is released, the three third compression springs 10 release the stored elastic potential energy in sync, pushing the horizontal plate 12 to drive the three long rods 27 to quickly exit and reset as a whole. There is no need to manually pull them out one by one, making the operation simple and efficient.

[0037] like Figure 1 , Figure 5As shown, one end of the quick reset assembly is equipped with three second cables 7, and the second cables 7 are electrically connected to the adjacent elastic contacts and the test host 4. The bottom of each of the three second cables 7 is fixedly connected to a second plug 18. One end of the second plug 18 is plugged into a second socket 19, and the second socket 19 is fixedly connected to the horizontal plate 12 and electrically connected to the copper contact 38. During diagnostic testing, the diagnostic pulse emitted by the test host 4 is transmitted to the horizontal plate 12 through the second cables 7, the second plug 18, and the second socket 19, and then injected into the copper rod 26 through the internal wire of the long rod 27, the first compression spring 32, the slider 30, and the copper contact 38, and finally enters the conductor of the cable 1. The reflected signal returns to the test host 4 along the same path for analysis and processing. The outer surfaces of the three first cables 6 and second cables 7 are all fixedly sleeved with a cable tray 5, and the cable tray 5 is fixedly connected to the test host 4. The cable tray 5 is a cable trough or cable tray structure made of insulating material, and is fixedly connected to the test host 4. It is used to uniformly and neatly fix multiple cables to avoid tangling and improve the neatness and maintenance convenience of the internal wiring of the device.

[0038] like Figure 1 , Figure 2 , Figure 3 , Figure 6 As shown, the outer surfaces of the three main cylinders 11 are all fixedly fitted with a support steel frame 2. One side of the outer surface of the support steel frame 2 is fixedly connected with an elastic buckle, and the elastic buckle matches the quick reset component. The elastic buckle includes a mounting plate 15, and the mounting plate 15 is fixedly connected to the support steel frame 2. Two tension springs 22 are symmetrically fixedly connected to the bottom of the mounting plate 15. The tension springs 22 are made of stainless steel spring wire. The bottom of the two tension springs 22 is fixedly connected to a movable frame 20. Two inclined blocks 21 are symmetrically fixedly connected to the top of the movable frame 20. The inclined blocks 21 are set through the mounting plate 15 and are slidably connected to the mounting plate 15. A handle 9 is fixedly connected to one side of the bottom of the movable frame 20. When unlocking is required, the operator only needs to pull the handle 9 down. The movable frame 20 overcomes the tension of the tension springs 22 and moves downward, driving the inclined blocks 21 downward.

[0039] Working principle: Cable 1 is in a live operating state, and the three phase wires supply power to the load side through the plug-in connection with T-type cable connector 3.

[0040] At this time, the coupling detection component is in continuous operation. On each phase T-type cable joint 3, the insulating ring 40 is embedded in the outer surface of the insulating jacket 13, and the detection ring 39 is located inside the insulating ring 40. The metal shielding ring 14 contacts the grounding metal partition of the ring main unit through the grounding plate 23, providing electromagnetic shielding for the detection ring 39. The detection ring 39 forms capacitive coupling with the internal high-voltage conductor through the insulation layer of the T-type cable joint 3, picking up high-frequency signals reflecting the insulation status of the cable 1. This signal is transmitted to the test host 4 through the first socket 16, the first plug 17, and the first cable 6, where the test host 4 performs online monitoring and analysis.

[0041] When online monitoring detects an anomaly or the scheduled maintenance cycle is reached, the maintenance personnel operate the ring main unit to open the load switch and close the grounding switch, de-energize cable 1 and reliably ground it. After the auxiliary contact of the grounding switch is closed, subsequent operations are performed.

[0042] The maintenance personnel hold the handrail 8 and, overcoming the initial resistance of the third compression spring 10 and the elastic buckle, push the horizontal plate 12 toward the main cylinder 11.

[0043] The horizontal plate 12 drives the three long rods 27 to move synchronously. As the long rods 27 advance, the front end of the copper contact 38 in the groove 31 will touch the closing plate 36. The copper contact 38 transmits the thrust to the first compression spring 32. The first compression spring 32 is compressed. At the same time, the copper contact 38 pushes open the closing plate 36. When the closing plate 36 flips, the inclined surface on its back pushes the inclined pressure rod 37 to rise. The inclined pressure rod 37 drives the slide plate 34 to slide in the housing 25. The slide plate 34 compresses the second compression spring 35.

[0044] After the closing plate 36 is fully pushed open, the copper contact 38 pops out and resets under the elastic force of the first compression spring 32. When the horizontal plate 12 continues to be pushed into place, the inclined block 21 in the elastic buckle resets under the tension of the tension spring 22, blocking and limiting the return movement of the horizontal plate 12, and limiting the horizontal plate 12 to the working position. At this time, the copper contact 38 forms an elastic pressure with the end face of the copper rod 26 under the elastic force of the first compression spring 32, establishing a stable metal-metal electrical contact.

[0045] During this period, the long rod 27 drives the piston ring 28 to slide along the inner wall of the inner cylinder 33, the volume of the inner cavity of the inner cylinder 33 decreases, the insulating medium filled inside is squeezed and enters the fixed cylinder 24, pushing the piston plate 29 to rise, achieving pressure difference balance, and ensuring the smooth movement of the long rod 27.

[0046] The diagnostic pulse emitted by the test host 4 passes through the second cable 7, the second plug 18, the second socket 19, the internal wire of the long rod 27, the first compression spring 32, the slider 30, the copper contact 38, and the copper rod 26, and is injected into the conductor of the cable 1. The reflected signal returns to the test host 4 along the same path.

[0047] The test host 4 injects broadband pulses or DC high voltage into the cable 1 through the diagnostic signal path, and at the same time receives the reflected wave signal to perform time-domain reflection positioning or quantitative evaluation of insulation resistance. The test host 4 switches from online monitoring mode to diagnostic test mode.

[0048] After the diagnostic test is completed, the test host 4 first executes the residual charge discharge procedure.

[0049] The maintenance personnel pull down the handle 9, and the movable frame 20 moves downward against the tension of the tension spring 22. The inclined plate block 21 disengages from the horizontal plate 12, releasing the restriction. Under the synchronous elastic force of the three third compression springs 10, the horizontal plate 12 drives the long rod 27 to pop out and reset. When the long rod 27 retracts, the copper contact 38 first disengages from the copper rod 26. Under the elastic force of the second compression spring 35, the closing plate 36 is quickly closed by the inclined surface push of the sliding plate 34 and the inclined pressure rod 37, re-sealing the outlet of the inner cylinder 33 and cutting off the weak electric arc that may be generated at the moment of separation between the copper contact 38 and the copper rod 26.

[0050] At the same time, the piston ring 28 also moves backward, the volume of the inner cavity of the inner cylinder 33 increases, and the piston plate 29 descends under the action of gravity, pressing the insulating medium in the fixed cylinder 24 back into the inner cylinder 33, thus achieving pressure differential balance again.

[0051] After the horizontal plate 12 is fully reset, the test host 4 switches back to the online monitoring mode. Then, the ring network cabinet is operated to open the grounding switch and close the load switch, and the cable 1 is restored to power. The coupling detection component continues to perform online monitoring.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A miniaturized cable testing device for ring main units, comprising a cable (1) and a testing host (4), characterized in that: The cable (1) is provided with three T-type cable connectors (3) above it, and the three phase wires of the cable (1) are fixedly plugged into the adjacent T-type cable connectors (3); Each of the three T-type cable connectors (3) has a test connector assembly fixedly inserted into one of its ports; The outer surfaces of the three detection connector assemblies are all fixedly fitted with coupling detection components, and the three coupling detection components are all electrically connected to the test host (4) via a first cable (6). One end of each of the three detection connector assemblies is fixedly connected to a main cylinder (11), and a differential pressure compensation assembly is fixedly connected to one side of the top of each of the three main cylinders (11). The inner surfaces of the three main cylinders (11) are all fixedly connected with inner cylinders (33), and the outlets of the three inner cylinders (33) are all hinged with closing plates (36). The three closing plates (36) are all installed with an elastic reset assembly between them and the main cylinders (11). The inner surfaces of the three inner cylinders (33) are all sealed and slidably connected with piston rings (28), and the inner surfaces of the three piston rings (28) are all fixedly connected with long rods (27). The three long rods (27) are all provided with grooves (31) at one end of the closing plate (36). The three grooves (31) are all equipped with elastic contacts, and the elastic contacts are matched with the detection connector assembly. The other ends of the three long rods (27) are fixedly connected to a quick reset assembly. One end of the quick reset assembly is equipped with three second cables (7), and the second cables (7) are electrically connected to the adjacent elastic contact and the test host (4). The outer surfaces of the three main cylinders (11) are all fixedly fitted with a support steel frame (2), and one side of the outer surface of the support steel frame (2) is fixedly connected with an elastic buckle, which is matched with the quick reset component.

2. The miniaturized cable testing device for ring main units according to claim 1, characterized in that: All three test connector assemblies include an insulating jacket (13), and the insulating jacket (13) is fixedly inserted into the adjacent port of the T-type cable connector (3). A copper rod (26) is fixedly connected to the inner surface of the insulating jacket (13), and the copper rod (26) is tightly abutted against the inner copper core of the adjacent port of the T-type cable connector (3).

3. A miniaturized cable testing device for ring main units according to claim 2, characterized in that: All three coupling detection components include an insulating ring (40), and the insulating ring (40) is fixedly embedded on the outer surface of the insulating jacket (13). The inner side of the insulating ring (40) is provided with a detection ring (39). A metal shielding ring (14) is fixedly sleeved on the outer surface of the insulating ring (40). A grounding plate (23) is fixedly connected to the bottom of the metal shielding ring (14).

4. A miniaturized cable testing device for ring main units according to claim 3, characterized in that: Each of the three first cables (6) is fixedly connected to a first plug (17) at its bottom. The bottom of the first plug (17) is connected to a first socket (16), and the first socket (16) is fixedly connected to the insulating jacket (13) and electrically connected to the adjacent detection ring (39).

5. A miniaturized cable testing device for ring main units according to claim 1, characterized in that: All three differential pressure compensation components include a fixed cylinder (24), and the fixed cylinder (24) is fixedly connected to the top of the main cylinder (11). The inner surface of the fixed cylinder (24) is sealed and slidably connected to a piston plate (29). The top of the fixed cylinder (24) has a through hole extending into the interior.

6. A miniaturized cable testing device for ring main units according to claim 1, characterized in that: All three elastic contacts include a first compression spring (32), and the first compression spring (32) is fixedly connected to the inner wall of one side of the groove (31). One end of the first compression spring (32) is fixedly connected to a slider (30), and the slider (30) is slidably connected to the inner wall of the groove (31). One end of the slider (30) is fixedly embedded with a copper contact (38).

7. A miniaturized cable testing device for ring main units according to claim 1, characterized in that: All three elastic reset components include a housing (25), and the housing (25) is fixedly connected to the top of the main cylinder (11). A sliding plate (34) is slidably connected to the inner surface of the housing (25). Two second compression springs (35) are fixedly connected to the top of the sliding plate (34) and the inner top wall of the housing (25). A slope pressure rod (37) is fixedly connected to the bottom of the sliding plate (34), and the slope of the slope pressure rod (37) slides against the slope of the closing plate (36).

8. A miniaturized cable testing device for ring main units according to claim 6, characterized in that: The quick reset assembly includes three third compression springs (10), and the third compression springs (10) are fixedly connected to one end of the inner cylinder (33) and sleeved on the outer surface of the long rod (27). The three third compression springs (10) and one end of the long rod (27) are fixedly connected to a horizontal plate (12), and a handrail (8) is fixedly connected to one side of the outer surface of the horizontal plate (12).

9. A miniaturized cable testing device for ring main units according to claim 8, characterized in that: The bottom of each of the three second cables (7) is fixedly connected to a second plug (18). One end of the second plug (18) is plugged into a second socket (19), and the second socket (19) is fixedly connected to the horizontal plate (12) and electrically connected to the copper contact (38). The outer surfaces of the three first cables (6) and second cables (7) are jointly fixedly fitted with a cable tray (5), and the cable tray (5) is fixedly connected to the test host (4).

10. A miniaturized cable testing device for ring main units according to claim 1, characterized in that: The elastic buckle includes a mounting plate (15), and the mounting plate (15) is fixedly connected to the supporting steel frame (2). Two tension springs (22) are symmetrically fixedly connected to the bottom of the mounting plate (15). The bottom of the two tension springs (22) is fixedly connected to a movable frame (20). Two inclined blocks (21) are symmetrically fixedly connected to the top of the movable frame (20). The inclined blocks (21) are set through the mounting plate (15) and are slidably connected to the mounting plate (15). A handle (9) is fixedly connected to one side of the bottom of the movable frame (20).

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