A high-voltage bushing for a neutral beam negative ion source

Abstract

This invention discloses a high-voltage bushing for a neutral beam negative ion source, belonging to the field of DC high-voltage power transmission. It includes a first voltage bushing assembly, a second voltage bushing assembly, two sets of ceramic insulating ring assemblies, two sets of fiber-reinforced plastic ring assemblies, a 0 kV flange assembly, and a housing, all coaxially mounted. This invention possesses excellent insulation capabilities, enabling the simultaneous transmission of two different voltages. Its simple and flexible structure allows for the addition of more bushings to transmit multiple voltages. It also solves the problem of sulfur hexafluoride (SF6) gas leakage from the transmission line, making it suitable for high-vacuum environments or other scenarios with stringent requirements regarding SF6 gas leakage.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of direct current high voltage transmission, and particularly relates to a high voltage bushing for a neutral beam negative ion source. BACKGROUND

[0002] In a particle accelerator system, especially a neutral beam negative ion source system, high voltage is often used to accelerate particles, and sulfur hexafluoride transmission lines are used to supply electric energy and other gases and liquid working media. The particle accelerator is in a vacuum environment, so it is necessary to transport high voltage electric energy and other working media from the sulfur hexafluoride insulated transmission line to the vacuum chamber. When the electric energy and the working media are transported to the vacuum chamber, the high voltage insulation capability of the sulfur hexafluoride side and the vacuum side needs to be ensured. For a high vacuum environment, the connection between the electrode and the insulating material needs to have excellent vacuum sealing performance. There is a large pressure difference between the sulfur hexafluoride insulated transmission line and the vacuum chamber, and the mechanical strength of the high voltage bushing installed between the sulfur hexafluoride insulated transmission line and the vacuum chamber needs to be ensured. The high voltage bushing of the prior art is usually applied to a tens of kilovolt power transmission scene, has poor insulation capability, is large in size, can only transport electric energy of one group of voltage, and does not consider the sulfur hexafluoride gas leakage rate, so it cannot ensure the sealing performance of the high vacuum demand, nor can it withstand the pressure brought by the higher pressure sulfur hexafluoride insulating gas required by the-400kV insulation. SUMMARY

[0003] To solve the above technical problems, the present application adopts the following technical solutions:

[0004] A high-voltage sleeve for a neutral beam negative ion source, comprising: coaxially installed first voltage sleeve assembly, second voltage sleeve assembly, two sets of ceramic insulating ring assembly, two sets of fiber reinforced plastic ring assembly, 0kV flange assembly, shell; the main part of the first voltage sleeve assembly and the second voltage sleeve assembly, two sets of ceramic insulating ring assembly, two sets of fiber reinforced plastic ring assembly, 0kV flange assembly are located inside the shell, part of the first voltage sleeve assembly and the second voltage sleeve assembly extend downward to the lower side of the shell and the 0kV flange assembly; the shell is installed on the upper side of the 0kV flange assembly, the upper side of the 0kV flange assembly, the inside of the shell, coaxially install the first set of ceramic insulating ring assembly and the first set of fiber reinforced plastic ring assembly, the first set of ceramic insulating ring assembly is arranged inside the first set of fiber reinforced plastic ring assembly; the upper side of the first set of ceramic insulating ring assembly and the first set of fiber reinforced plastic ring assembly coaxially installs the second voltage sleeve assembly; the upper side of the second voltage sleeve assembly coaxially installs the second set of ceramic insulating ring assembly and the second set of fiber reinforced plastic ring assembly, the second set of ceramic insulating ring assembly is arranged inside the second set of fiber reinforced plastic ring assembly; the upper side of the second set of ceramic insulating ring assembly and the second set of fiber reinforced plastic ring assembly coaxially installs the first voltage sleeve assembly; the top of the shell is connected with the shell of the sulfur hexafluoride insulated transmission line; the first set of ceramic insulating ring assembly and the first set of fiber reinforced plastic ring assembly are used for insulation between the second voltage sleeve assembly and the 0kV flange assembly; the second set of ceramic insulating ring assembly and the second set of fiber reinforced plastic ring assembly are used for insulation between the first voltage sleeve assembly and the second voltage sleeve assembly; wherein the first voltage is greater than the second voltage.

[0005] The present application has the following beneficial effects:

[0006] The present application uses a coaxial cylindrical electrode structure, and coaxial ceramic rings and fiber reinforced plastic rings are used as double-layer insulating rings between the electrodes. Air with a pressure greater than sulfur hexafluoride gas is filled between the double-layer insulating rings. The present application has good insulation capacity, can simultaneously transmit two groups of electric energy with different voltages, and has a simple and flexible structure, and the number of sleeve assemblies can be freely increased to transmit multiple groups of electric energy with different voltages, and simultaneously solves the problem of sulfur hexafluoride gas leakage from the transmission line, and can be used in high-vacuum environments or other scenes with strict requirements on sulfur hexafluoride gas leakage. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1This is a cross-sectional view of the high-voltage bushing for a neutral beam negative ion source according to the present invention, wherein: 1-0kV flange, 6-200kV flange, 7-200kV cylindrical electrode, 8-equalizing ring, 9-cooling water pipe, 10-cylindrical electric field shield, 11-400kV flange, 12-400kV cylindrical electrode, 13-top cover, 16-outer shell, 52-first ceramic insulating ring, 54-first fiber-reinforced plastic ring, 62-second ceramic insulating ring. Ring, 64-Second fiber reinforced plastic ring, 114-First cathode electric stress ring, 215-First anode electric stress ring, 214-Second cathode electric stress ring, 315-Second anode electric stress ring, 531-First metal ring, 532-Second metal ring, 551-First clamping metal ring, 552-Second clamping metal ring, 631-Third metal ring, 632-Fourth metal ring, 651-Third clamping metal ring, 652-Fourth clamping metal ring;

[0008] Figure 2 This is a perspective view of a -200kV bushing assembly for a neutral beam negative ion source according to the present invention, wherein 9-cooling water pipe, 171-first cooling water channel, and 172-second cooling water channel;

[0009] Figure 3 This is a cross-sectional schematic diagram of the first set of ceramic insulating rings in the high-voltage bushing of the neutral beam negative ion source of the present invention, wherein 52-first ceramic insulating ring, 531-first metal ring, and 532-second metal ring. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0011] The following uses two different voltage values, -400kV (first voltage) and -200kV (second voltage), as examples to illustrate the specific implementation of the present invention.

[0012] like Figure 1 As shown, the high-voltage bushing used for the neutral beam negative ion source includes: a -400kV bushing assembly, a -200kV bushing assembly, two sets of ceramic insulating ring assemblies, two sets of fiber-reinforced plastic ring assemblies, a 0 kV flange assembly, and a housing 16.

[0013] All components and the housing 16 are coaxially installed, the housing 16 is installed on the upper side of the 0kV flange assembly, the installation (or connection) of the main body of other components is located inside the housing 16, and part of the -400kV sleeve assembly and the -200kV sleeve assembly extend downward to the lower side of the housing 16 and the 0kV flange assembly.

[0014] The housing 16 is installed on the upper side of the 0kV flange assembly, the first set of ceramic insulating ring assemblies and the first set of fiber reinforced plastic ring assemblies are coaxially installed on the upper side of the 0kV flange assembly and inside the housing 16, and the first set of ceramic insulating ring assemblies are arranged inside the first set of fiber reinforced plastic ring assemblies.

[0015] The first set of ceramic insulating ring assemblies and the first set of fiber reinforced plastic ring assemblies are coaxially installed on the upper side of the -200kV sleeve assembly, part of the -200kV sleeve assembly extends downward to the inside of the first set of ceramic insulating ring assemblies and the 0kV flange assembly, and axially extends out of the outside of the 0kV flange assembly.

[0016] The second set of ceramic insulating ring assemblies and the second set of fiber reinforced plastic ring assemblies are coaxially installed on the upper side of the -200kV sleeve assembly, and the second set of ceramic insulating ring assemblies are arranged inside the second set of fiber reinforced plastic ring assemblies.

[0017] The second set of ceramic insulating ring assemblies and the second set of fiber reinforced plastic ring assemblies are coaxially installed on the upper side of the -400kV sleeve assembly, part of the -400kV sleeve assembly extends downward to the inside of the second set of ceramic insulating ring assemblies, the -200kV sleeve assembly, the first set of ceramic insulating ring assemblies, and the 0kV flange assembly, and axially extends out of the outside of the -200kV sleeve assembly.

[0018] The -400kV sleeve assembly includes a cover 13, a -400kV flange 11, a -400kV cylindrical electrode 12, and a first cathode electric stress ring 114.

[0019] The -200kV sleeve assembly includes a -200kV flange 6, a -200kV cylindrical electrode 7, a cooling water pipe 9, a cylindrical electric field shielding cover 10, a grading ring 8, a second cathode electric stress ring 214, and a first anode electric stress ring 215.

[0020] The ceramic insulating ring assembly includes a ceramic insulating ring and a metal ring. The first set of ceramic insulating ring assemblies includes a first ceramic insulating ring 52, a first metal ring 531, and a second metal ring 532, and the second set of ceramic insulating ring assemblies includes a second ceramic insulating ring 62, a third metal ring 631, and a fourth metal ring 632. The two sets of ceramic insulating ring assemblies have the same structure.

[0021] The fiber-reinforced plastic ring assembly includes a fiber-reinforced plastic ring and a compression metal ring. Specifically, the first fiber-reinforced plastic ring assembly includes a first fiber-reinforced plastic ring 54, a first compression metal ring 551, and a second compression metal ring 552; the second fiber-reinforced plastic ring assembly includes a second fiber-reinforced plastic ring 64, a third compression metal ring 651, and a fourth compression metal ring 652. Both sets of fiber-reinforced plastic ring assemblies have the same structure.

[0022] The 0kV flange assembly includes a 0kV flange 1 and a second anode stress ring 315.

[0023] The first set of ceramic insulating ring assemblies and the first set of fiber-reinforced plastic ring assemblies are used for insulation between the -200kV bushing assembly and the 0kV flange assembly; the second set of ceramic insulating ring assemblies and the second set of fiber-reinforced plastic ring assemblies are used for insulation between the -400kV bushing assembly and the -200kV bushing assembly.

[0024] A housing 16 is mounted on the upper side of the 0kV flange assembly, containing the main body of the -400kV bushing assembly and the -200kV bushing assembly, as well as the ceramic insulation ring assembly and the fiber-reinforced plastic ring assembly. The top of the housing 16 is connected to the housing of the sulfur hexafluoride insulated transmission line. Figure 1 (Not shown in the image).

[0025] Furthermore, in the -400kV bushing assembly, a -400kV flange 11 is installed on the lower side of the upper cover 13, a -400kV cylindrical electrode 12 is installed inside the -400kV flange 11, the lower end of the -400kV cylindrical electrode 12 extends out of the outer shell 16, and a first cathode electrical stress ring 114 is installed on the lower side of the -400kV flange 11.

[0026] Furthermore, in the -200kV bushing assembly, a second cathode stress ring 214 is installed on the lower side of the -200kV flange 6, a first anode stress ring 215 is installed on the upper side of the -200kV flange 6, and a -200kV cylindrical electrode 7 is installed on the inner side of the -200kV flange 6. The -200kV cylindrical electrode 7 is fitted onto the outer side of the middle section of the -400kV cylindrical electrode 12, and its lower end extends out of the outer shell 16. Its lower end has a conical opening structure, and a voltage equalizing ring 8 with the same diameter as the lower end of the opening is installed on the lower side of the conical opening structure. Multiple sets of cooling water pipes 9 are radially installed on the outer surface of the -200kV cylindrical electrode 7, and a cylindrical electric field shield 10 is installed on the outer side of the cooling water pipes 9.

[0027] Furthermore, in the 0kV flange assembly, a second anode stress ring 315 is installed on the upper side of the 0kV flange 1.

[0028] Further, the high voltage bushing for neutral beam negative ion source of the present application has the space between the outer side of the upper cover 13, the -400kV flange 11, the second group of fiber reinforced plastic ring assembly, the -200kV flange 6 and the first group of fiber reinforced plastic ring assembly, the inner side of the shell 16 and the upper side of the 0kV flange 1 filled with sulfur hexafluoride gas with a pressure of 0.6MPa, and the space with sulfur hexafluoride gas is in communication with the sulfur hexafluoride insulated transmission line.

[0029] Further, the high voltage bushing for neutral beam negative ion source of the present application has the space between the inner side of the -400kV flange 11, the second group of ceramic insulating ring assembly, the -200kV flange 6 and the first group of ceramic insulating ring assembly, the outer side of the -400kV cylindrical electrode 12 and the lower side of the 0kV flange 1 as a vacuum environment.

[0030] Further, the dry air with a pressure of 1MPa is provided between each group of ceramic insulating ring assembly and fiber reinforced plastic ring assembly to prevent the sulfur hexafluoride gas from leaking into the vacuum environment and affecting the working performance of the vacuum unit.

[0031] Further, as shown in Figure 3 the first metal ring 531 and the second metal ring 532 are located on the upper side and the lower side of the first ceramic insulating ring 52. The upper side and the lower side of the first ceramic insulating ring 52 are respectively fixed by brazing with the first metal ring 531 and the second metal ring 532; the third metal ring 631 and the fourth metal ring 632 are located on the upper side and the lower side of the second ceramic insulating ring 62; the upper side and the lower side of the second ceramic insulating ring 62 are respectively fixed by brazing with the third metal ring 631 and the fourth metal ring 632. The two groups of ceramic insulating ring assemblies have the same structure, and in each group of ceramic insulating ring assembly, the upper side and the lower side of the ceramic insulating ring are respectively fixed by brazing with two metal rings, and the four metal rings of the two groups of ceramic insulating ring assemblies are respectively tightly fixed on the upper side of the 0kV flange 1, the upper side and the lower side of the -200kV flange 6 and the lower side of the -400kV flange 11 by screws, and rubber sealing rings are installed between the metal rings and the 0kV flange 1, the -200kV flange 6 and the -400kV flange 11 for sealing between the vacuum chamber and the dry air.

[0032] Further, in each fiber reinforced plastic ring assembly, the upper end and the lower end of the outer side of the fiber reinforced plastic ring are each provided with a ring of protruding structures, and four compressed metal rings are used to clamp the protruding structures of the two fiber reinforced plastic ring assemblies, and the two fiber reinforced plastic ring assemblies are fixed between the upper side of the 0 kV flange 1 and the lower side of the -200 kV flange 6, and between the upper side of the -200 kV flange 6 and the lower side of the -400 kV flange 11 by screw compression, and rubber sealing rings are installed between the two fiber reinforced plastic rings and the upper side of the 0 kV flange 1, the upper side and the lower side of the -200 kV flange 6, and the lower side of the -400 kV flange 11, for sealing between the dry air between the ceramic insulating ring assembly and the fiber reinforced plastic ring assembly and the sulfur hexafluoride gas outside the fiber reinforced plastic ring assembly.

[0033] Further, the -400 kV cylindrical electrode 12 is internally provided with various low-voltage cables and fluid working medium delivery pipelines, and is connected to the ion source of the accelerator in the vacuum chamber on the lower side, and delivers electric energy, provides cooling water and gas working medium, etc. to the ion source.

[0034] Further, the upper side of the upper cover 13 is connected to the -400 kV electrode of the sulfur hexafluoride insulated transmission line (not shown in the figure) Figure 1 , and the -400 kV electrode of the sulfur hexafluoride insulated transmission line is internally provided with various low-voltage cables and fluid working medium delivery pipelines, and the various low-voltage cables and fluid working medium enter the interior of the -400 kV cylindrical electrode 12 through the upper cover 13.

[0035] Further, as shown in the figure Figure 2 , the -200 kV flange 6 is internally provided with a first cooling water flow channel 171, and the radially inner side of the first cooling water flow channel 171 in the -200 kV flange 6 is connected to the upper end of the cooling water pipeline 9, and the radially outer side of the first cooling water flow channel 171 in the -200 kV flange 6 is connected to the -200 kV electrode of the sulfur hexafluoride insulated transmission line (not shown in the figure) Figure 2 .

[0036] Further, the equalizing ring 8 is used to improve and reduce the electric field distribution at the lower end of the -200 kV cylindrical electrode 7, and to reduce the electric field intensity on the surface of the electrode. The equalizing ring 8 is internally provided with a second cooling water flow channel 172, and the upper side of the second cooling water flow channel 172 is connected to the lower end of the cooling water pipeline 9, and the lower side of the second cooling water flow channel 172 in the equalizing ring 8 is connected to the accelerator electrode (not shown in the figure) Figure 2 in the vacuum chamber, and provides cooling water to the accelerator electrode.

[0037] Further, the first cathode electric stress ring 114, the second cathode electric stress ring 214, the first anode electric stress ring 215, and the second anode electric stress ring 315 are used to improve and reduce the electric field intensity on the surface of the ceramic insulating ring, and to reduce the electric field intensity at the junction of the vacuum, metal and ceramic insulating material.

[0038] Further, the lower side surface of the -400kV flange 11, the upper side surface and the lower side surface of the -200kV flange 6 and the upper side surface of the 0kV flange 1 are respectively provided with annular protruding structures between the ceramic insulating ring assembly and the fiber reinforced plastic ring assembly, for improving the electric field distribution near the first ceramic insulating ring 52, the second ceramic insulating ring 62, the first fiber reinforced plastic ring 54 and the second fiber reinforced plastic ring 64.

[0039] Further, the number of groups of high voltage bushing transmission voltage can be expanded by adding a proper number of bushing assemblies of other voltages similar to the structure of the -200kV bushing assembly, and adding a corresponding number of ceramic insulating ring assemblies and fiber reinforced plastic ring assemblies. Similar to the structure of the -200kV bushing assembly means that the flange structure of the added bushing assemblies of other voltages is the same as the structure and size of the -200kV flange 6, and the cylindrical electrode of the added bushing assemblies of other voltages is the same as the structure of the -200kV cylindrical electrode 7, but the diameter and length of the cylindrical electrode of the added bushing assemblies of other voltages are different from the diameter and length of the -200kV cylindrical electrode 7.

[0040] Preferably, the overall diameter of the high voltage bushing can be increased to increase the insulation distance between the electrodes for adapting to higher voltage use. The structure and connection mode of the flanges, ceramic insulating ring assemblies and fiber reinforced plastic ring assemblies of different voltages in the bushing are the same, and the number of bushing assemblies of other voltages can be conveniently expanded by adding flanges, ceramic insulating ring assemblies, fiber reinforced plastic ring assemblies of other voltages and cylindrical electrodes of different diameters and lengths, for increasing the transmission of more groups of electric energy of other voltages.

[0041] The present application uses two groups of coaxial electrodes with different radii to transmit -400kV and -200kV high voltage electric energy from the transmission line into the vacuum chamber, and transmits low voltage electric energy, cooling water and gas working medium through the internal space of the -400kV electrode, and transmits cooling water through the cooling water flow channel on the -200kV electrode.

[0042] The present application has better insulation capacity, can transmit electric energy of two groups of voltages, and has a simple and flexible structure, can transmit electric energy of more than two groups of voltages by freely increasing the number of bushing assemblies, and at the same time solves the problem of leakage of sulfur hexafluoride gas out of the transmission line, can be used in the high vacuum environment of a neutral beam negative ion source, or other scenes with strict requirements on gas leakage.

Claims

1. A high voltage feedthrough for a neutral beam negative ion source, characterized by, The application relates to a coaxial installation of a first voltage bushing assembly, a second voltage bushing assembly, two sets of ceramic insulation ring assemblies, two sets of fiber-reinforced plastic ring assemblies, a 0kV flange assembly and a shell (16); the main parts of the first voltage bushing assembly and the second voltage bushing assembly, the two sets of ceramic insulation ring assemblies, the two sets of fiber-reinforced plastic ring assemblies and the 0kV flange assembly are located inside the shell (16), and a part of the first voltage bushing assembly and the second voltage bushing assembly extends downwards to the lower side of the shell (16) and the 0kV flange assembly; the shell (16) is installed on the upper side of the 0kV flange assembly, the upper side of the 0kV flange assembly and the inside of the shell (16) are coaxially installed with the first set of ceramic insulation ring assemblies and the first set of fiber-reinforced plastic ring assemblies, the first set of ceramic insulation ring assemblies are arranged inside the first set of fiber-reinforced plastic ring assemblies; the upper side of the first set of ceramic insulation ring assemblies and the first set of fiber-reinforced plastic ring assemblies is coaxially installed with the second voltage bushing assembly; the upper side of the second voltage bushing assembly is coaxially installed with the second set of ceramic insulation ring assemblies and the second set of fiber-reinforced plastic ring assemblies, the second set of ceramic insulation ring assemblies are arranged inside the second set of fiber-reinforced plastic ring assemblies; the upper side of the second set of ceramic insulation ring assemblies and the second set of fiber-reinforced plastic ring assemblies is coaxially installed with the first voltage bushing assembly; the top of the shell (16) is connected with the shell of a sulfur hexafluoride insulation transmission line; the first set of ceramic insulation ring assemblies and the first set of fiber-reinforced plastic ring assemblies are used for insulation between the second voltage bushing assembly and the 0kV flange assembly; the second set of ceramic insulation ring assemblies and the second set of fiber-reinforced plastic ring assemblies are used for insulation between the first voltage bushing assembly and the second voltage bushing assembly; wherein the first voltage is greater than the second voltage. The first voltage bushing assembly comprises a cover (13), a first voltage flange (11), a first voltage cylindrical electrode (12) and a first cathode electric stress ring (114); the lower side of the cover (13) is installed with the first voltage flange (11), the inner side of the first voltage flange (11) is installed with the first voltage cylindrical electrode (12), the lower end of the first voltage cylindrical electrode (12) extends out of the shell (16), and the lower side of the first voltage flange (11) is installed with the first cathode electric stress ring (114).

2. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 1, characterized in that: The second voltage bushing assembly comprises a second voltage flange (6), a second voltage cylindrical electrode (7), a cooling water pipeline (9), a cylindrical electric field shielding cover (10), a voltage equalizing ring (8), a second cathode electric stress ring (214) and a first anode electric stress ring (215); the lower side of the second voltage flange (6) is installed with the second cathode electric stress ring (214), the upper side of the second voltage flange (6) is installed with the first anode electric stress ring (215), and the inner side of the second voltage flange (6) is installed with the second voltage cylindrical electrode (7); the second voltage cylindrical electrode (7) is sleeved outside the middle segment of the first voltage cylindrical electrode (12), and the lower end of the second voltage cylindrical electrode (7) extends out of the shell (16).

3. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 2, characterized in that: ​ 4. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 3, characterized in that: The lower end of the second voltage cylindrical electrode (7) is provided with a conical opening structure, the lower side of the conical opening structure is provided with an equal-diameter voltage equalizing ring (8), a plurality of groups of cooling water pipes (9) are radially arranged on the outer side surface of the second voltage cylindrical electrode (7), and a cylindrical electric field shielding cover (10) is arranged on the outer side of the cooling water pipes (9).

5. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 4, characterized in that: The ceramic insulating ring assembly comprises a ceramic insulating ring and a metal ring; a first group of ceramic insulating ring assemblies comprises a first ceramic insulating ring (52), a first metal ring (531) and a second metal ring (532), and a second group of ceramic insulating ring assemblies comprises a second ceramic insulating ring (62), a third metal ring (631) and a fourth metal ring (632); the first metal ring (531) and the second metal ring (532) are located on the upper side and the lower side of the first ceramic insulating ring (52); the upper side and the lower side of the first ceramic insulating ring (52) are respectively brazed and fixed with the first metal ring (531) and the second metal ring (532); the third metal ring (631) and the fourth metal ring (632) are located on the upper side and the lower side of the second ceramic insulating ring (62); and the upper side and the lower side of the second ceramic insulating ring (62) are respectively brazed and fixed with the third metal ring (631) and the fourth metal ring (632).

6. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 5, characterized in that: The first metal ring (531), the second metal ring (532), the third metal ring (631) and the fourth metal ring (632) are respectively tightly fixed on the upper side of the 0kV flange (1), the upper side and the lower side of the second voltage flange (6) and the lower side of the first voltage flange (11) by screws, and rubber sealing rings are arranged between the 0kV flange (1), the second voltage flange (6) and the first voltage flange (11).

7. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 6, characterized in that: The fiber reinforced plastic ring assembly comprises a fiber reinforced plastic ring and a compression metal ring; a first fiber reinforced plastic ring assembly comprises a first fiber reinforced plastic ring (54), a first compression metal ring (551) and a second compression metal ring (552), and a second fiber reinforced plastic ring assembly comprises a second fiber reinforced plastic ring (64), a third compression metal ring (651) and a fourth compression metal ring (652); the upper end and the lower end of the outer side of the first fiber reinforced plastic ring (54) and the second fiber reinforced plastic ring (64) each have a ring of protruding structures, the first compression metal ring (551), the second compression metal ring (552), the third compression metal ring (651) and the fourth compression metal ring (652) are used for clamping the protruding structures, and the two groups of fiber reinforced plastic ring assemblies are respectively fixed between the upper side of the 0kV flange (1) and the lower side of the second voltage flange (6) and between the upper side of the second voltage flange (6) and the lower side of the first voltage flange (11) by screw compression, and rubber sealing rings are arranged between the two fiber reinforced plastic rings and the upper side of the 0kV flange (1), the upper side and the lower side of the second voltage flange (6) and the lower side of the first voltage flange (11).

8. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 7, characterized in that: The 0kV flange assembly comprises a 0kV flange (1) and a second anode electric stress ring (315), and the second anode electric stress ring (315) is arranged on the upper side of the 0kV flange (1).

9. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 8, characterized in that: The outer side of the upper cover (13), the first voltage flange (11), the second group of fiber reinforced plastic ring assemblies, the second voltage flange (6) and the first group of fiber reinforced plastic ring assemblies, the inner side of the outer shell (16) and the upper side of the 0kV flange (1) have a space with a pressure of 0.6MPa of sulfur hexafluoride gas, and the space with sulfur hexafluoride gas is in communication with the sulfur hexafluoride insulated transmission line.

10. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 9, characterized in that: The inner side of the first voltage flange (11), the second group of ceramic insulating ring assemblies, the second voltage flange (6) and the first group of ceramic insulating ring assemblies, the outer side of the first voltage cylindrical electrode (12) and the lower side of the 0kV flange (1) are in a vacuum environment; each group of ceramic insulating ring assemblies and fiber reinforced plastic ring assemblies have a pressure of 1MPa of dry air.

11. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 10, characterized in that: The equalizing ring (8) is used to improve and reduce the electric field distribution of the lower end of the second voltage cylindrical electrode (7), and reduce the electric field intensity of the electrode surface; the equalizing ring (8) has a second cooling water channel (172) inside, the upper side of the second cooling water channel (172) inside the equalizing ring (8) is connected with the lower end of the cooling water pipeline (9), and the lower side of the second cooling water channel (172) inside the equalizing ring (8) is connected with the accelerator electrode in the vacuum chamber and provides cooling water to the accelerator electrode.

12. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 11, characterized in that: The second voltage flange (6) is provided with a first cooling water channel (171) inside, the radially inner side of the first cooling water channel (171) inside the second voltage flange (6) is connected with the upper end of the cooling water pipeline (9), and the radially outer side of the first cooling water channel (171) inside the second voltage flange (6) is connected with the second voltage electrode of the sulfur hexafluoride insulated transmission line.

13. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 12, characterized in that: The equalizing ring (8) has a second cooling water channel (172) inside, the upper side of the second cooling water channel (172) is connected with the lower end of the cooling water pipeline (9), and the lower side of the second cooling water channel (172) inside the equalizing ring (8) is connected with the accelerator electrode in the vacuum chamber.

14. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 13, characterized in that: The lower side surface of the first voltage flange (11), the upper side surface and the lower side surface of the second voltage flange (6) and the upper side surface of the 0kV flange (1) are respectively provided with annular protruding structures, which are located between the first group of ceramic insulating ring assemblies and the first group of fiber reinforced plastic ring assemblies or between the second group of ceramic insulating ring assemblies and the second group of fiber reinforced plastic ring assemblies, and are used to improve the electric field distribution near the first ceramic insulating ring (52), the second ceramic insulating ring (62), the first fiber reinforced plastic ring (54) and the second fiber reinforced plastic ring (64).

15. A high voltage feedthrough for a neutral beam negative ion source as defined in claim 14, characterized in that: By increasing a predetermined number of other voltage sleeve assemblies similar to the structure of the second voltage sleeve assembly and increasing a corresponding number of ceramic insulating ring assemblies and fiber reinforced plastic ring assemblies, the number of groups of transmission voltages of the high voltage sleeve is expanded; the similar structure to the second voltage sleeve assembly is that the flange structure of the increased other voltage sleeve assembly is the same as the structure and size of the second voltage flange (6), the cylindrical electrode is the same as the structure of the second voltage cylindrical electrode (7), and the diameter and length of the cylindrical electrode are different from the diameter and length of the second voltage cylindrical electrode (7).

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