±160 kV Low-temperature Superconducting Bushings

Abstract

The present invention discloses a ±160 kV cryogenic superconducting bushing, which relates to a superconducting bushing. The normal temperature end of the high-toughness dry-type capacitor core passes through the flange, and an anti-rotation module is provided between the flange and the flange plate. Both ends of the pollution-proof insulating sleeve are respectively connected to the flange and the connecting plate, and an insulating layer is arranged between the pollution-proof insulating sleeve and the high-toughness dry-type capacitor core; the core is welded to the measuring terminal through a lead, a current-diverting ring is assembled on the core, a conductive rod is arranged inside the core, a terminal is welded at the end of the conductive rod, and the heat insulation component penetrated by the extending end of the conductive rod is fixed on the connecting plate, and a temperature isolation layer is formed between the heat insulation component and the isolation pad. The present invention realizes a dry-type structure with high mechanical strength, no oil and no gas, good sealing performance, and maintenance-free, meets the requirements of high-voltage operation and test environments from room temperature to supercooled liquid nitrogen temperature region and ±160 kV, realizes the transition from superconducting to normal conducting, from low temperature to normal temperature, and from high voltage to low voltage, and also realizes the connection transition between superconducting and conventional circuits, with broad application prospects.

Description

Technical Field

[0001] The present invention relates to a superconducting bushing, and particularly to a ±160 kV cryogenic superconducting bushing that includes a transition from superconducting to normal conduction, from low temperature to normal temperature, and from high voltage to low voltage, and realizes the connection transition between superconducting and conventional lines. Background Art

[0002] With the continuous growth of the transmission grid capacity and the continuous improvement of the interconnection degree between power grids, the short-circuit fault current levels of many current power grids have exceeded or are about to exceed the range that the existing line circuit breakers can handle, posing a great hidden danger to the safe operation of the power grid. To improve the stability, safety, reliability, and power quality of the power system, superconducting devices for power lines have been developed. Considering the control of processing technology, partial discharge, and low-temperature performance, the structure of dry-type capacitor bushings is more likely to meet the electric field control of superconducting terminals. With the increase in voltage level, the product structure, performance reliability, and stability become particularly important. Therefore, it is imperative to develop cryogenic superconducting bushings with high voltage levels. Based on this, it is particularly necessary to design a new type of ±160 kV cryogenic superconducting bushing. Summary of the Invention

[0003] Aiming at the deficiencies in the prior art, the object of the present invention is to provide a ±160 kV cryogenic superconducting bushing with a reasonable structural design, which realizes the transition from superconducting to normal conduction, from low temperature to normal temperature, and from high voltage to low voltage, and also realizes the connection transition between superconducting and conventional lines, meets the electric field control of superconducting terminals, effectively improves the stability, safety, and reliability of the power system, and is easy to promote and use.

[0004] To achieve the above object, the present invention is realized by the following technical solutions: a ±160 kV cryogenic superconducting bushing, including a terminal board, a conductive rod, a grading shield, a heat insulation component, a connecting plate, a seal, a fastener, a high-toughness dry-type capacitor core, a pollution-proof insulating sleeve, a heat insulation layer, an insulating layer, a current-dividing ring, a flange, a measuring terminal, an anti-rotation module, a flange plate, an isolation pad, a terminal post, a grading ball, an on-line monitoring device and an insulating interface. The high-toughness dry-type capacitor core is provided with a normal-temperature end and a low-temperature end. The normal-temperature end of the high-toughness dry-type capacitor core passes through the flange. The flange is fixedly connected to the flange plate. An anti-rotation module is arranged between the flange and the flange plate. The pollution-proof insulating sleeve is fixed on the flange. The connecting plate is fixed on the pollution-proof insulating sleeve. The two ends of the pollution-proof insulating sleeve are respectively connected to the flange and the connecting plate. The on-line monitoring device and the insulating interface are installed on the flange through valves. An insulating layer is arranged between the pollution-proof insulating sleeve and the high-toughness dry-type capacitor core; the high-toughness dry-type capacitor core is connected to the measuring terminal through a lead. A current-dividing ring is assembled on the high-toughness dry-type capacitor core. The fastener is fixed to the normal-temperature end of the high-toughness dry-type capacitor core by a thread. The seal is fixed to the fastener by a bolt. The conductive rod penetrates through the core of the high-toughness dry-type capacitor core. The end of the conductive rod is welded with a terminal post. The grading ball is fixed on the terminal post. The extending end of the conductive rod penetrates into the heat insulation component. The heat insulation component is fixed to the connecting plate by a bolt. A heat insulation layer is formed between the heat insulation component and the isolation pad. The grading shield is fixed on the connecting plate. The terminal board is also installed on the conductive rod through a hoop bolt.

[0005] Preferably, the high-toughness dry-type capacitor core is internally provided with a DC capacitor screen and an AC capacitor screen. Leads are respectively led out from the DC capacitor screen and the AC capacitor screen and welded to the measuring terminal. There are multiple measuring terminals, including voltage terminals and end-screen terminals; the high-toughness dry-type capacitor core is specially processed and assembled with a current-dividing ring to prevent the accumulation of static charges.

[0006] Preferably, the high-toughness dry-type capacitor core is formed by impregnating nano-scale super-tough glass fiber with flexible super-tough epoxy resin on a microcomputer-controlled machine tool and solidifying it through a process, meeting the requirements of room temperature to sub-cooled liquid nitrogen temperature range, ±160 kV high-voltage operation and test environment.

[0007] Preferably, the flange is clamped on the periphery of the high-toughness dry-type capacitor core at a specified position through a core platform. The flange plate passes through the low-temperature end of the high-toughness dry-type capacitor core and is firmly installed with the flange. The anti-rotation module arranged between the two can prevent the core from rotating.

[0008] Preferably, the pollution-proof insulating sleeve adopts an insulating sleeve with a six-umbrella - three-combination mode, having the characteristics of corrosion resistance and high pollution-proof level.

[0009] Preferably, the insulating layer between the high-toughness dry-type capacitor core and the peripheral anti-pollution insulating sleeve is filled through an insulating interface to ensure the electrical performance of the bushing.

[0010] Preferably, the conductive rod is a conductive rod made of superconducting material. A terminal is welded on the conductive rod, and the two are inserted into the low-temperature end of the high-toughness dry-type capacitor core together. A heat-insulating component that combines heat insulation and evacuation is connected through a connecting plate. A heat-insulating layer with a vacuum adiabatic structure is formed between the conductive rod and the high-toughness dry-type capacitor core through the heat-insulating component at the top and the isolating pad at the bottom to reduce the overall heat leakage of the high-voltage outgoing line.

[0011] The beneficial effects of the present invention are as follows: The device realizes a dry structure with high mechanical strength, is oil-free and gas-free, has good sealing performance, is maintenance-free, has strong pollution resistance, and meets the requirements from room temperature to supercooled liquid nitrogen temperature range, ±160 kV high-voltage operation and test environment. It realizes the transition from superconducting to normal conduction, from low temperature to normal temperature, from high voltage to low voltage, and also realizes the connection transition between superconducting and conventional circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will be described in detail below with reference to the drawings and specific embodiments;

[0013] Figure 1 It is a schematic structural diagram of the present invention;

[0014] Figure 2 It is a schematic structural diagram of the six-umbrella - three-combined umbrella type of the anti-pollution insulating sleeve of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0016] Refer to Figure 1-2, the present specific implementation adopts the following technical solutions: a ±160 kV cryogenic superconducting bushing, including a terminal board 1, a conductive rod 2, a grading shield 3, a heat insulation component 4, a coupling plate 5, a seal 6, a fastener 7, a high-toughness dry-type capacitor core 8, a pollution-proof insulating sleeve 9, a heat insulation layer 10, an insulating layer 11, a current-dividing ring 12, a flange 13, a measuring terminal 14, an anti-rotation module 15, a flange plate 16, an isolation pad 17, a terminal post 18, a grading ball 19, an on-line monitoring device 20 and an insulating interface 21. The high-toughness dry-type capacitor core 8 is provided with a normal-temperature end and a low-temperature end. The normal-temperature end of the high-toughness dry-type capacitor core 8 passes through the flange 13. The flange 13 is fixedly connected to the flange plate 16. An anti-rotation module 15 is arranged between the flange 13 and the flange plate 16. The pollution-proof insulating sleeve 9 is fixed on the flange 13. The coupling plate 5 is fixed on the pollution-proof insulating sleeve 9. The two ends of the pollution-proof insulating sleeve 9 are respectively connected to the flange 13 and the coupling plate 5. The on-line monitoring device 20 and the insulating interface 21 are installed on the flange 13 through valves. An insulating layer 11 is arranged between the pollution-proof insulating sleeve 9 and the high-toughness dry-type capacitor core 8; the high-toughness dry-type capacitor core 8 is connected to the measuring terminal 14 through a lead. The current-dividing ring 12 is assembled on the high-toughness dry-type capacitor core 8. The fastener 7 is thread-locked on the high-toughness dry-type capacitor core 8. The seal 6 is connected to the fastener 7 through a bolt. The conductive rod 2 passes through the core of the high-toughness dry-type capacitor core 8. The end of the conductive rod 2 is welded with the terminal post 18. The grading ball 19 is fixed on the terminal post 18. The extending end of the conductive rod 2 penetrates into the heat insulation component 4. The heat insulation component 4 is fixed on the coupling plate 5 through a bolt. A heat insulation layer 10 is formed between the heat insulation component 4 and the isolation pad 17. The grading shield 3 is fixed on the coupling plate 5, which not only plays a grading role but also leaves a position to hide the heat insulation component 4, saving a part of the bushing space. The terminal board 1 is tightened on the conductive rod 2 through a hoop bolt.

[0017] It should be noted that the high-toughness dry-type capacitor core 8 impregnates nano-scale super-tough glass fiber with flexible super-tough epoxy resin on a microcomputer-controlled machine tool and is cured and formed through a special process to meet the room temperature to supercooled liquid nitrogen temperature range, ±160 kV high-voltage operation and test environment. Its main functions include the transition from superconducting to normal conduction, from low temperature to normal temperature, and from high voltage to low voltage, realizing the connection and transition between superconducting and conventional circuits; and the high-toughness dry-type capacitor core 8 is internally provided with a DC capacitor screen and an AC capacitor screen. Leads are respectively led out from the DC capacitor screen and the AC capacitor screen and welded to the measuring terminal 14. There are multiple measuring terminals 14, including voltage terminals and end-screen terminals; the high-toughness dry-type capacitor core 8 is specially processed and assembled with a current-dividing ring 12 to prevent the accumulation of static charges.

[0018] The flange 13 is clamped at a specified position on the periphery of the high-toughness dry-type capacitor core 8 through a core platform. The flange plate 16 passes through the low-temperature end of the high-toughness dry-type capacitor core 8 and is firmly installed with the flange, and an anti-rotation module 15 is arranged between the two to prevent the core from rotating at an angle.

[0019] The anti-fouling insulating sleeve 9 described above adopts an insulating sleeve with a six-umbrella - three-combination mode, breaking the conventional large and small umbrella-shaped structure mode, with a more novel structure, and the shape is as Figure 2 shown, and it has the characteristics of corrosion resistance and high pollution resistance level.

[0020] The insulating layer 11 between the high-toughness dry-type capacitor core 8 described above and the surrounding anti-fouling insulating sleeve 9 is filled through the insulating interface 2 to ensure the electrical performance of the bushing.

[0021] In addition, the conductive rod 2 described above is a conductive rod made of superconducting material. The wiring terminal 18 is welded on the conductive rod 2, and the two together penetrate from the low-temperature end of the high-toughness dry-type capacitor core 8. The heat insulation component 4 with both heat insulation and evacuation functions is connected to the connection plate 5 through the fastening device. A heat insulation layer 10 with a vacuum heat insulation structure is formed between the conductive rod 2 and the high-toughness dry-type capacitor core 8 through the heat insulation component 4 at the top and the isolation pad 17 at the bottom, reducing the overall heat leakage of the high-voltage outgoing line.

[0022] The specific implementation steps of this specific implementation method are as follows:

[0023] (1) On a microcomputer machine tool, impregnate nano-scale super-tough glass fiber with flexible super-tough epoxy resin, and wind and cure it into a high-toughness dry-type capacitor core 8 through a special process;

[0024] (2) Stand the high-toughness dry-type capacitor core 8 upright, and its normal-temperature end passes through the flange 13, and the DC panel lead and the AC panel lead are respectively inserted into their respective flange terminal seats;

[0025] (3) Install the anti-rotation module 15, pass the flange plate 16 through from the low-temperature end, and connect the flange 13 and the flange plate 16 together through the fastening device;

[0026] (4) Weld and install the measuring terminal 14;

[0027] (5) Weld the current-dividing ring 12 on the high-toughness dry-type capacitor core 8;

[0028] (6) Fix the fastener 7 on the normal-temperature end of the high-toughness dry-type capacitor core 8 through threads, and fasten the seal 6 on the fastener 7 through bolts;

[0029] (7) Pass the anti-fouling insulating sleeve 9 through the normal-temperature end of the high-toughness dry-type capacitor core 8, and fix it on the flange 13 through the fastening device;

[0030] (8) Fix the connection plate 5 on the anti-fouling insulating sleeve 9 through the fastening device;

[0031] (9) Insert the conductive rod 2 welded with the wiring terminal 18 into the core from the low-temperature end of the high-toughness dry-type capacitor core 8;

[0032] (10) Insert the heat insulation component 4 through the protruding end of the conductive rod 2 and fix it on the connection plate 5 with fastening bolts;

[0033] (11) Install the grading hood 3 on the conductive rod 2 and fix it through the fastening device;

[0034] (12) Install the wiring board 1 and tighten it on the conductive rod 2 through the hoop bolts;

[0035] (13) Fasten the grading ball 19 to the terminal post 18;

[0036] (14) Install the on-line monitoring device 20 and the insulation interface 21 on the flange 13 through valves;

[0037] (15) Fill the insulating layer 11 into the bushing through the insulation interface 21;

[0038] (16) Finally, use special equipment to perform interlayer heat insulation treatment on the bushing to form the heat insulation layer 10.

[0039] It should be noted that in step (1), first, the epoxy resin is made ductile by debugging, proportioning auxiliary materials, and heating. On the microcomputer numerical control machine tool, the pre-treated flexible and super-ductile epoxy resin is impregnated with nano-scale super-ductile glass fibers. By controlling the radial insulation thickness and the axial end gradient, the uniform distribution of the radial field strength and the axial field strength is achieved, and the winding is completed. Then, by controlling the curing temperature, it is formed into the high-ductility dry-type capacitor core 8.

[0040] The realization of the heat insulation layer 10 in step (16): The isolation pad 17 at the bottom of the bushing and the upper heat insulation component 4 isolate the low-temperature end environment, the normal-temperature end environment from the inside of the bushing. The bushing conductive rod 2 is made of superconducting material, and its conductivity changes with the temperature, so as to control the current-carrying capacity of the bushing. The interlayer heat insulation device between the two forms the heat insulation layer 10 through a vacuum pumping device, ensuring that the inside is a whole vacuum insulation structure. This structure not only realizes superconductivity but also reduces the overall heat leakage of the high-voltage outgoing line.

[0041] The superconducting bushing in this specific embodiment is of a dry-type capacitive structure, without the need to fill any insulating medium inside, completely avoiding the problems of oil leakage and air leakage in other bushings. The insulating bushing of this structure has extremely high mechanical strength and toughness against high and low temperatures at the same time; by adopting the principle of series and parallel capacitor plates, the AC and DC special effects are achieved; the special current-diverting ring design avoids the concentrated distribution of charges; the novel insulating sleeve endows it with strong anti-fouling flashover ability and strong pollution resistance; the heat insulation device of the bushing realizes a vacuum insulation structure, reducing the overall heat leakage of the high-voltage outgoing line; thus ensuring the safe and reliable transmission of electric energy, meeting the requirements from room temperature to supercooled liquid nitrogen temperature range, ±160 kV high-voltage operation and test environment, realizing the transition from superconducting to normal conduction, from low temperature to normal temperature, from high voltage to low voltage, and also realizing the connection transition between superconducting and conventional lines, with broad market application prospects.

[0042] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only used to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. ±160 kV cryogenic superconducting bushing, Characterized in that, it includes a terminal board (1), a conductive rod (2), a grading cover (3), a heat insulation component (4), a connecting plate (5), a seal (6), a fastener (7), a high-toughness dry-type capacitor core (8), a pollution-proof insulating sleeve (9), a heat insulation layer (10), an insulating layer (11), a current bypass ring (12), a flange (13), a measuring terminal (14), an anti-rotation module (15), a flange plate (16), an isolation pad (17), a terminal post (18), a grading ball (19), an on-line monitoring device (20) and an insulating interface (21). The high-toughness dry-type capacitor core (8) has a normal-temperature end and a low-temperature end. The normal-temperature end of the high-toughness dry-type capacitor core (8) passes through the flange (13). The flange (13) is fixedly connected to the flange plate (16). An anti-rotation module (15) is arranged between the flange (13) and the flange plate (16). A pollution-proof insulating sleeve (9) is fixed on the flange (13). A connecting plate (5) is fixed on the pollution-proof insulating sleeve (9). The two ends of the pollution-proof insulating sleeve (9) are respectively connected to the flange (13) and the connecting plate (5). An on-line monitoring device (20) and an insulating interface (21) are installed on the flange (13) through valves. An insulating layer (11) is arranged between the pollution-proof insulating sleeve (9) and the high-toughness dry-type capacitor core (8); the high-toughness dry-type capacitor core (8) is connected to the measuring terminal (14) through a lead. A current bypass ring (12) is assembled on the high-toughness dry-type capacitor core (8). The normal-temperature end of the high-toughness dry-type capacitor core (8) is fixed with a fastener (7) by threads. A seal (6) is fixed on the fastener (7) by bolts. A conductive rod (2) is arranged inside the core of the high-toughness dry-type capacitor core (8). A terminal post (18) is welded at the end of the conductive rod (2). A grading ball (19) is fixed on the terminal post (18). The extending end of the conductive rod (2) penetrates into a heat insulation component (4). The heat insulation component (4) is fixed on the connecting plate (5) by bolts. A heat insulation layer (10) is formed between the heat insulation component (4) and the isolation pad (17). A grading cover (3) is fixed on the connecting plate (5). A terminal board (1) is also installed on the conductive rod (2) through a hoop bolt; The high-toughness dry-type capacitor core (8) internally contains a DC capacitor screen and an AC capacitor screen. The DC capacitor and the AC capacitor are respectively led out to the measuring terminal (14) through leads; The high-toughness dry-type capacitor core (8) is obtained by impregnating nano-level super-tough glass fibers with flexible super-tough epoxy resin on a microcomputer-controlled machine tool. By controlling the radial insulation thickness and the axial gradient at both ends, the uniform distribution of the radial field strength and the axial field strength is realized, and winding is completed. Then, by controlling the curing temperature, it is formed to meet the requirements from room temperature to supercooled liquid nitrogen temperature range, ±160 kV high-voltage operation and test environment; The flange (13) is clamped around the high-toughness dry-type capacitor core (8) through a core platform. The flange plate (16) passes through the low-temperature end of the high-toughness dry-type capacitor core (8) and is firmly installed with the flange. The anti-rotation module arranged between the two can prevent the core from rotating; The anti-fouling insulating sleeve (9) described is an insulating sleeve adopting a six-umbrella - three-combination mode, which is corrosion-resistant and pollution-resistant; The insulating layer (11) between the highly ductile dry-type capacitor core (8) and the peripheral anti-fouling insulating sleeve (9) is filled through an insulating interface (21) to ensure the electrical performance of the bushing; The conductive rod (2) described is a conductive rod made of superconducting material. A terminal post is welded on the conductive rod. The two together penetrate into the low-temperature end of the highly ductile dry-type capacitor core (8). The heat insulation component (4) with heat insulation and evacuation functions is connected through a connection plate (5). A vacuum-insulated heat insulation layer (10) is formed between the conductive rod (2) and the highly ductile dry-type capacitor core (8) through the heat insulation component (4) at the top and the isolation pad (17) at the bottom to reduce the overall heat leakage of the high-voltage outgoing line.

2. The ±160 kV low-temperature superconducting bushing according to claim 1, characterized in that The grading cover (3) described is fixed on the connection plate (5) to play a grading role, and a position for hiding the heat insulation component (4) is reserved inside the grading cover (3) to save the space of the bushing.

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