A kind of high voltage insulation current lead for superconductive electric device
Technical field
The present invention relates to a kind of current feed of superconducting power device, particularly low temperature, High-Voltage Insulation current feed.
Background technology
Superconducting Power Technology is the novel electric power technology that the physical characteristic of utilizing the without hindrance high density current capacity of superconductor and the superconducting state of superconductor-normal state to change grows up, the fail safe that can improve the quality of electric energy, the stability that improves power system operation and reliability, reduction electric pressure, improves electrical network; The transmission capacity that can greatly improve single-machine capacity and electrical network also reduces the loss of electrical network greatly; The quality of power supply of regenerative resource be can greatly improve, and itself and large electrical network effective connection made.
In the last few years, the research and development of Superconducting Power Technology had obtained major progress, and the superconducting power devices such as superconductive current limiter, superconducting transformer, superconductive energy storage system have entered the demonstrating running stage.All superconducting power devices are all to operate under certain low temperature environment, the most general technology is that the core components such as superconducting coil are assemblied in the good low-temperature (low temperature) vessel of heat-insulating property, the cold-producing mediums such as liquid nitrogen or liquid helium are injected low-temperature (low temperature) vessel do not have the devices such as superconducting coil, also have only a few to utilize heat conducting method cryocooled.
No matter adopt which kind of cooling means, the current feed of the superconducting devices such as superconducting coil all will be transitioned into from room temperature-196 ℃ or lower low temperature environment.Superconducting device in the past, high-intensity magnetic field superconducting coil of using as therapeutic medical nulcear magnetic resonance (NMR), scientific experiment etc., all to be operated under direct current, stable situation, voltage between lead-in wire and low-temperature (low temperature) vessel and lead-in wire only has several volts to tens volts, reduces by room temperature to the heat conduction of low temperature so main current feed technology all concentrates on.And the current feed of the related superconducting device of the Superconducting Power Technology that latest developments are got up, except considering the heat conduction, what want most is the high-voltage insulation issue of current feed.Because superconducting device nearly all is operated under high-voltage state, High-Voltage Insulation level between lead-in wire and low-temperature (low temperature) vessel (usually low-temperature (low temperature) vessel ground connection), between going between, not only be related to the stable operation of equipment, more concern installation, operations staff's personal safety.And current feed is transitioned into-196 ℃ from room temperature, and not only temperature is low but also the temperature difference is large, and conventional insulation technology is difficult to meet the demands.Current feed generally adopts the red copper material that resistivity is little, conduct electricity very well, and the heat conductivity of copper is good, adds the temperature difference large, and exposed lead-in wire outside low-temperature (low temperature) vessel very easily bears water or frost, and this high-voltage insulation technique to lead-in wire is had higher requirement.At present still do not have reliable, ripe technology to solve or overcome the problems referred to above.
Current feed in the pulse high-voltage situation also has research (IEEE Transactions on Applied Superconductivity, vol.10, no.1,2000, pp1477), mainly use the GAS-COOLED CURRENT LEAD under the liquid helium cooling condition, what the technology emphasis solved is to be engaged in temperature to the leakage heat problem of liquid helium warm area; What relevant High-Voltage Insulation was adopted is that technical scheme is at very large stainless steel tube of diameter of current feed overcoat, in fill mobile nitrogen, adopt the nitrogen spacer insulator.This pin configuration is complicated, and adopts the nitrogen gas insulating that flows, and insulation level is subjected to the impact of nitrogen temperature, mobility status very large, and the High-Voltage Insulation ability is unstable; Due to venthole being arranged, very easily freeze, water or dew, the insulation of current feed there is fatal destruction.
Summary of the invention
The objective of the invention is to overcome the defectives such as complex structure, insulating capacity that prior art exists be unstable, propose a kind of low temperature High-Voltage Insulation thread guide devices, the present invention can be widely used in room temperature in the excessive high voltage superconducting power device of low temperature.
High-Voltage Insulation current feed of the present invention is mainly by red copper conductor, insulating sleeve, wiring nose, insulator, sealing O circle, and the parts such as low-temperature (low temperature) vessel flange form.
Described red copper conductor is the red copper bar of an even thickness, an end of red copper conductor, and namely low-temperature end is inserted in low-temperature (low temperature) vessel, and the end of described low-temperature end is prefabricated into binding post; The other end of red copper conductor, namely indoor temperature end stretches out outside low-temperature (low temperature) vessel; Filled with liquid nitrogen or liquid helium in low-temperature (low temperature) vessel.The length of red copper conductor is l.Described insulating sleeve selects frp pipe or G10 tubing to make, the insulating sleeve length l ' and than the short 3~7cm of the length l of red copper conductor.Insulating sleeve is sleeved on outside the red copper conductor, and the external diameter of the internal diameter of insulating sleeve and red copper conductor closely cooperates, and makes the indoor temperature end of red copper conductor outside low-temperature (low temperature) vessel expose approximately 2~5cm of insulating sleeve.The indoor temperature end of wiring nose and red copper conductor exposes the end crimping of insulating sleeve part, jointly forms the insulator pin main body.
It is l that the medium position of insulating sleeve has length
2Screw thread.It is l that the indoor temperature end of insulating sleeve has length
1Hermetic terminal, l
1Be not less than 30cm, this hermetic terminal is used for and being tightly connected of conventional electric power cable, and the hermetic terminal external diameter is not more than the minimum diameter of insulating sleeve threaded portion.According to the electrical insulation characteristics of rated voltage and the insulating sleeve material of superconducting device, the pipe thickness t of hermetic terminal satisfies following formula:
t=5+kU/u (1)
In formula, t is the pipe thickness of hermetic terminal, and unit is mm; U is the rated voltage of superconducting device, the kV of unit; U is the puncture voltage of the every mm thickness of insulating sleeve material, and unit is kV; K is under different electric pressures, the ratio of U and one minute industrial frequency withstand voltage.
The low-temperature (low temperature) vessel flange is the cover plate of sealing low-temperature (low temperature) vessel, and separates low-temperature (low temperature) vessel and room temperature space.The accessory of insulation current of the present invention lead-in wire mainly comprises insulator, sealing O circle and nut, and insulator, sealing O circle and nut are mainly used in the sealing, waterproof of insulation current lead-in wire and low-temperature (low temperature) vessel flange, fixing and reinforced insulation etc.Sealing O circle and insulator are fixed on the low-temperature (low temperature) vessel flange by nut, their relative position relation is as follows: lower nut is positioned at the bottommost of insulating sleeve middle part screw thread, lower seal O circle is above lower nut, the low-temperature (low temperature) vessel flange is above lower seal O circle, the top of low-temperature (low temperature) vessel flange is middle sealing O circle, insulator, upper sealing O circle, top nut successively, and screw, and coaxial with the insulator pin main body.Lower nut and top nut are fixed on all accessories on the low-temperature (low temperature) vessel flange vertically.The vertical range of the indoor temperature end of insulating sleeve and low-temperature (low temperature) vessel flange is not less than 60cm.The low-temperature end of insulation current lead-in wire is placed in low-temperature (low temperature) vessel, and the low-temperature end termination of insulation current lead-in wire is below the liquid level of liquid nitrogen or liquid helium, so that being connected and cooling red copper conductor of lead-in wire and superconducting device.
Because the reduction along with temperature of the resistance of red copper reduces, when the liquid nitrogen temperatures of-196 ℃ only are room temperature 1/8.In order to reduce the heat conduction of current feed from the room temperature to low temperature, the part of red copper conductor below the low-temperature (low temperature) vessel flange also can be for variable cross-section, the impact of Joule heat when considering galvanization simultaneously, the cross section of red copper conductor low-temperature end may be selected to be 1/4~1/2 of its indoor temperature end cross section.The internal orifice dimension of insulating sleeve and red copper conductor closely cooperate, and other structures of insulator pin are all constant.
The present invention is by special construction and the annex and the demand that has satisfied coordinating of low-temperature (low temperature) vessel from room temperature to the low temperature environment high-temperature gradient of insulator pin, the heat that also effectively reduces from the room temperature to the low temperature environment by red copper conductor variable section structure is conducted, and the more important thing is an effective high-voltage insulation technique difficult problem that has solved current feed.The present invention can be widely used on the superconduct devices such as superconductive current limiter, energy storage, transformer.
Description of drawings
Fig. 1 low temperature High-Voltage Insulation lead-in wire schematic diagram, Fig. 1 a is low temperature High-Voltage Insulation lead member structure chart, and Fig. 1 b is the rear low temperature High-Voltage Insulation lead-in wire of assembling schematic diagram, in figure: 1 red copper conductor, 2 prefabricated binding posts, 3 insulating sleeves, 4 screw threads, 5 hermetic terminals, 6 wiring noses, 7 insulator pin main bodys, the length of l red copper conductor 1, l
2The length of screw thread 4, l
1The length of hermetic terminal 5, the indoor temperature end of A red copper conductor 1, the low-temperature end of B red copper conductor 1, the indoor temperature end of C insulating sleeve 3, the low-temperature end of D insulating sleeve 3, the indoor temperature end of E insulator pin main body 7, the low-temperature end of F insulator pin main body 7;
The assembling position of Fig. 2 low temperature High-Voltage Insulation lead-in wire and annex thereof concerns schematic diagram, in figure: 8 lower nuts, 9 lower seal O circles, sealing O circle in 10,11 insulators, sealing O circle on 12,13 top nuts;
Low temperature High-Voltage Insulation lead-in wire and annex schematic diagram thereof after Fig. 3 assembling are in figure: 14 low-temperature (low temperature) vessel flanges, l
3Insulator pin 7 outdoor section length;
Fig. 4 variable cross-section red copper conductor schematic diagram is in figure: 15 variable cross-section red copper conductors, the indoor temperature end of A ' variable cross-section red copper conductor 15, the low-temperature end of B ' variable cross-section red copper conductor.
Embodiment
Further illustrate the present invention below in conjunction with the drawings and specific embodiments.
Low temperature High-Voltage Insulation of the present invention lead-in wire mainly by: red copper conductor 1, insulating sleeve 3, wiring nose 6, insulator 11, lower seal O circle 9, middle sealing O circle 10, upper sealing O enclose 12 and the parts such as low-temperature (low temperature) vessel flange 14 form.
As shown in Figure 1a, red copper conductor 1 is the red copper bar of an even thickness, and the low-temperature end B of red copper conductor 1 inserts in low-temperature (low temperature) vessel, and the end of the low-temperature end B of red copper conductor 1 has prefabricated binding post 2, and the length of red copper conductor 1 is l.Insulating sleeve 3 is selected the material that has the good electrical insulation property, has at low temperatures good mechanical performance, usually selects frp pipe.The length l of insulating sleeve 3 ' than the short 3~7cm of the length l of red copper conductor 1.The external diameter of the internal diameter of insulating sleeve 3 and red copper conductor 1 closely cooperates, the indoor temperature end A of red copper conductor 1 inserts in insulating sleeve 3 from the indoor temperature end C of insulating sleeve 3, and the about 2~5cm of the indoor temperature end C that the indoor temperature end A of red copper conductor 1 is exposed insulating sleeve 3, the wiring nose 6 that red copper is made and the end crimping that the indoor temperature end A of red copper conductor 1 exposes insulating sleeve 3 parts form the insulator pin main body 7 as shown in Fig. 1 b.
It is l that the medium position of insulating sleeve 3 has length
2Screw thread 4, be used for the accessories such as insulator pin main body 7 and insulator 11, sealing O circle, nut are fixed on low-temperature (low temperature) vessel flange 14; The indoor temperature end C of insulating sleeve 3 is that length is l
1Hermetic terminal 5, l
1Length be not less than 30cm, hermetic terminal 5 is used for being tightly connected of insulation current lead-in wire main body 7 and conventional electric power cable.The external diameter of hermetic terminal 5 is not more than the minimum diameter of screw thread 4 bottoms of thread.According to the electrical insulation characteristics of rated voltage and the insulating sleeve material of superconducting device, the pipe thickness t of hermetic terminal 5 satisfies described formula (1).
As shown in Figure 2, the accessory of insulator pin main body 7 mainly comprises lower nut 8, lower seal O circle 9, middle sealing O circle 10, insulator 11, upper sealing O circle 12, top nut 13 etc., described accessory be mainly used in insulator pin main body 7 and low-temperature (low temperature) vessel flange 14 sealing, waterproof, fix and reinforced insulation etc.Screw thread 4 length l on insulating sleeve
2Be not less than the axial length sum of all accessories.As shown in Figure 2, position relationship between accessory is as follows: lower nut 8 is at the bottommost of insulating sleeve 3 middle part screw threads 4, lower seal O circle 9 is above lower nut 8, low-temperature (low temperature) vessel flange 14 is above sealing O circle 9, and the top of low-temperature (low temperature) vessel flange 14 is middle sealing O circle 10, insulator 11, upper sealing O circle and top nut 13 successively.As shown in Figure 3, low-temperature (low temperature) vessel flange 14 is cover plates of sealing low-temperature (low temperature) vessel.Insulator pin main body 7 is passed the hole on low-temperature (low temperature) vessel flange 14, and lower nut 8 is fixed on insulator pin main body 7 and accessory on low-temperature (low temperature) vessel flange 14 with top nut 13.The indoor temperature end C of insulating sleeve 3 and the vertical range of low-temperature (low temperature) vessel flange 14 be less than 60cm, below the liquid level of the low-temperature end F of insulator pin main body 7 liquid nitrogen or liquid helium in low-temperature (low temperature) vessel.Low temperature High-Voltage Insulation thread guide devices after assembling as shown in Figure 3.
Because the reduction along with temperature of the resistance of red copper reduces, when the liquid nitrogen temperatures of-196 ℃ only are room temperature 1/8.In order to reduce to go between the heat conduction of main body 7 from the room temperature to low temperature, what red copper conductor 1 can be for variable cross-section in the part of low-temperature (low temperature) vessel flange below 14.The impact of Joule heat when considering galvanization simultaneously, the red copper conductor adopts the variable cross-section frustum cone structure from low-temperature (low temperature) vessel flange position to its low-temperature end, and the cross section of the low-temperature end of red copper conductor is 1/4~1/2 of its indoor temperature end cross section.As shown in Figure 4, variable cross-section red copper conductor 15 ' from low-temperature (low temperature) vessel flange position adopts the variable cross-section frustum cone structure to a section of its low-temperature end B '.The internal orifice dimension of insulating sleeve 3 is similar to the variable section structure of variable cross-section red copper conductor 15, and the internal orifice dimension of insulating sleeve 3 both closely cooperates than the large 0.2~0.5mm of external diameter of variable cross-section red copper conductor 15, and other structures of low temperature High-Voltage Insulation thread guide devices are all constant.