阅读说明：本技术 一种高压直流输电换流阀阻尼吸收回路用电容器 (Capacitor for damping absorption loop of high-voltage direct-current transmission converter valve ) 是由 路伟 李好群 戴永然 于 2021-08-28 设计创作，主要内容包括：本发明公开了一种高压直流输电换流阀阻尼吸收回路用电容器,本发明,包括顶部绝缘端子、外壳、上盖、电容芯包、接地端子,所述外壳内部设置有电容芯包,所述外壳的顶部设置有上盖,所述电容芯包顶端与顶部绝缘端子相连,所述电容芯包顶端与接地端子相连从而实现与外壳等电位联结,所述顶部绝缘端子与上盖的上下端配合处设有装配底座和密封圈,所述电容芯包底端设有电工圆纸板与金属曲面垫。本发明,保证电容器无容量衰减及自愈失效特性,通过多内串和外串工艺、真空注气处理有效保证耐电压性能和降低局部放电效应,大大提高产品的可靠性。(The invention discloses a capacitor for a damping absorption loop of a high-voltage direct-current transmission converter valve, which comprises a top insulating terminal, a shell, an upper cover, a capacitor core package and a grounding terminal, wherein the capacitor core package is arranged in the shell, the upper cover is arranged at the top of the shell, the top end of the capacitor core package is connected with the top insulating terminal, the top end of the capacitor core package is connected with the grounding terminal so as to realize equipotential connection with the shell, an assembly base and a sealing ring are arranged at the matching position of the top insulating terminal and the upper end and the lower end of the upper cover, and an electrician round paperboard and a metal curved surface pad are arranged at the bottom end of the capacitor core package. The invention ensures that the capacitor has no capacity attenuation and self-healing failure characteristics, effectively ensures the voltage resistance and reduces the partial discharge effect through a multi-inner-series and outer-series process and vacuum gas injection treatment, and greatly improves the reliability of the product.)

1. The utility model provides a high voltage direct current transmission converter valve damping absorption circuit capacitor, includes top insulation terminal (1), shell (2), upper cover (3), electric capacity core package (4), ground terminal (5), its characterized in that: the utility model discloses a capacitor core package, including shell (2), top are provided with upper cover (3), capacitor core package (4) top links to each other with top insulation terminal (1), thereby capacitor core package (4) top links to each other with ground terminal (5) and realizes the equipotential connection with the shell, top insulation terminal (1) is equipped with assembly base (6) and sealing washer with the upper and lower end cooperation department of upper cover (3), capacitor core package (4) bottom is equipped with electrician circle cardboard (8) and metal curved surface pad (9).

2. The capacitor for the damping absorption circuit of the HVDC converter valve according to claim 1, wherein: the capacitor core package (4) comprises a lower capacitor core (11), an upper capacitor core (12), an upper locating sleeve (13), a lower locating sleeve (14), a supporting round electrical paper board (15), an upper fixing resin plate (16), an upper locating ring (17), a middle locating ring (18), a lower locating ring (19), a pressure isolating device (20), a flexible cable (21), a high-voltage insulating sleeve (22), a connecting copper bar (23) and an insulating protective sleeve (24), wherein the lower capacitor core (11) and the upper capacitor core (12) are arranged inside the insulating protective sleeve (24), the lower capacitor core (11) and the upper capacitor core (12) are connected in series through the connecting copper bar (23), and the lower capacitor core (11) and the upper capacitor core (12) are connected in series through the supporting round electrical paper board (15), the upper fixing resin plate (16) and the upper locating ring (17), Well holding ring (18), lower holding ring (19) are fixed, electric capacity core (11) and pressure isolating device (20) down and go up electric capacity core (12) and be connected through the mode of soldering with flexible cable (21), the bottom of electric capacity core (11) is provided with down position sleeve (14) down, the top of going up electric capacity core (12) is provided with position sleeve (13), the surface cover of pressure isolating device (20) is equipped with high-voltage insulation sleeve (22).

3. The capacitor for the damping absorption circuit of the HVDC converter valve according to claim 2, wherein: the lower and upper capacitor cores (11, 12) include a polypropylene film (25), an electrical aluminum foil (26), a hollow core rod (27), and the polypropylene film (25), the polypropylene film (25) and the electrical aluminum foil (26) being combined with each other in a laminate form and wound around the outer surface of the hollow core rod (27).

4. The capacitor for the damping absorption circuit of the HVDC converter valve according to claim 1, wherein: the top insulating terminal (1) and the assembling base (6) are made of modified PBT materials.

5. The capacitor for the damping absorption circuit of the HVDC converter valve according to claim 1, wherein: and an insulating filling layer (10) formed by filling sulfur hexafluoride and nitrogen mixed insulating gas after vacuum is filled between the capacitor core package (4) and the electrical round paper board (8) and between the capacitor core package and the metal curved pad (9).

6. The capacitor for the damping absorption circuit of the HVDC converter valve according to claim 1, wherein: the shell (2) is made of aluminum and is subjected to frosted oxidation treatment, the upper cover (3) is provided with a hole sealing hole, and the outer surface of the shell (2) is provided with an overpressure buffering device (7).

7. The capacitor for the damping absorption circuit of the HVDC converter valve according to claim 3, wherein: electrician's aluminium foil (26) and polypropylene film (25) make electrician's aluminium foil outstanding formation out of paper tinsel (28) through the dislocation, electrician's aluminium foil (26) and polypropylene film (25) make electrician's aluminium foil flexible formation limit (29) through the dislocation, through forming in between electrician's aluminium foil (26) limit (30).

8. The capacitor for the damping absorption circuit of the HVDC converter valve according to claim 3, wherein: the polypropylene film (25) is designed to be coarsened on two sides.

9. The capacitor for the damping absorption circuit of the HVDC converter valve according to claim 3, wherein: the electrical aluminum foil (26) has a thickness of 5 μm.

10. The capacitor for the damping absorption circuit of the HVDC converter valve according to claim 3, wherein: the insulating protective sleeve (24) is made of polyester materials.

Technical Field

The invention relates to the technical field of capacitors, in particular to a capacitor for a damping absorption loop of a high-voltage direct-current transmission converter valve.

Background

High Voltage Direct Current (HVDC) is high power long distance DC transmission with stable DC power and no inductive reactance, capacitive reactance, synchronization, etc. and the transmission process is DC. Are commonly used for long distance transmission of electrical energy via overhead lines and submarine cables, and in some applications not suitable for conventional ac coupling, are also used for coupling between independent electrical systems. By using the high-voltage direct-current transmission system, both the level and the direction of electric energy can be controlled quickly and accurately, and the performance can improve the performance and the efficiency of an alternating-current power grid connected with the high-voltage direct-current transmission system, so that the direct-current transmission system is generally applied.

The converter valve is core equipment of a direct current transmission project, expected direct current voltage is obtained by sequentially connecting three-phase alternating current voltage to a direct current end, power control is achieved, and the value of the converter valve accounts for 22-25% of the total price of complete equipment of a converter station. The converter valve comprises a thyristor, a damping capacitor, a voltage-sharing capacitor, a damping resistor, a voltage-sharing resistor, a saturable reactor, a thyristor control unit and other parts. Because the thyristor has poor overcurrent and overvoltage capacity and cannot work normally without reliable protection measures, the RC absorption loop is very important and is a component without possibility or shortage.

Damping absorption capacitors as core protection elements currently rely on importation mainly for damping capacitors. In recent years, accidents such as capacity attenuation, combustion and explosion frequently occur along with the occurrence of imported metallized capacitors, so that the safe operation of equipment such as a converter valve, an SVC (static var compensator), a rectifier cabinet and the like is seriously influenced, and serious accidents and economic losses are caused.

Practical contents

The invention aims to provide a capacitor for a damping absorption loop of a high-voltage direct-current transmission converter valve, which solves the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: the utility model provides a capacitor for damping absorption circuit of high voltage direct current transmission converter valve, includes top insulation terminal, shell, upper cover, electric capacity core package, ground terminal, the inside electric capacity core package that is provided with of shell, the top of shell is provided with the upper cover, electric capacity core package top links to each other with top insulation terminal, thereby electric capacity core package top links to each other with ground terminal and realizes the equipotential connection with the shell, top insulation terminal is equipped with assembly base and sealing washer with the upper and lower end cooperation department of upper cover, electric capacity core package bottom is equipped with electrician's circle cardboard and metal curved surface pad.

Preferably, the capacitor core package comprises a lower capacitor core, an upper locating sleeve, a lower locating sleeve, a supporting round electrical paper board, an upper fixing resin plate, an upper locating ring, a middle locating ring, a lower locating ring, a pressure isolating device, a flexible cable, a high-voltage insulating sleeve, a connecting copper bar and an insulating protective sleeve, wherein the lower capacitor core and the upper capacitor core are arranged in the insulating protective sleeve, the lower capacitor core and the upper capacitor core are connected in series through the connecting copper bar, the lower capacitor core and the upper capacitor core are fixed through the supporting round electrical paper board, the upper fixing resin plate, the upper locating ring, the middle locating ring and the lower locating ring, the lower capacitor core and the pressure isolating device as well as the upper capacitor core and the flexible cable are connected in a soldering mode, the lower locating sleeve is arranged at the bottom of the lower capacitor core, the upper locating sleeve is arranged at the top of the upper capacitor core, and a high-voltage insulating sleeve is sleeved on the outer surface of the pressure isolating device.

Preferably, the lower and upper capacitor cores include a polypropylene film, an electrical aluminum foil, a hollow core rod, and a polypropylene film combined with the electrical aluminum foil in a laminate form and wound around an outer surface of the hollow core rod.

Preferably, the top insulating terminal and the assembly base are made of modified PBT materials.

Preferably, the insulation filling layer formed by sulfur hexafluoride and nitrogen mixed insulation gas is filled between the capacitor core package and the electrical round paper board and between the capacitor core package and the metal curved pad after vacuum.

Preferably, the shell adopts aluminium to make and dull polish oxidation treatment, the upper cover is equipped with the hole sealing, the surface of shell is provided with over pressure buffer.

Preferably, electrician's aluminium foil and polypropylene film make electrician's aluminium foil outstanding formation out of the paper tinsel through the dislocation, electrician's aluminium foil and polypropylene film make electrician's aluminium foil flexible formation through the dislocation and reserve the limit, reserve the limit through forming between the electrician's aluminium foil.

Preferably, the polypropylene film is of a double-sided coarsening design.

Preferably, the electrical aluminum foil is 5 μm thick.

Preferably, the insulating protective sleeve is made of a polyester material.

Compared with the prior art, the invention has the beneficial effects that: the capacitor for the damping absorption loop of the high-voltage direct-current transmission converter valve ensures that the capacitor has no capacity attenuation and self-healing failure characteristics, effectively ensures voltage resistance and reduces partial discharge effect through multiple inner series and outer series processes and vacuum gas injection treatment, and greatly improves the reliability of products.

Drawings

FIG. 1 is a schematic cross-sectional view of the structure of the present invention;

FIG. 2 is a schematic cross-sectional view of a capacitor core package according to the present invention;

FIG. 3 is a schematic diagram of a capacitor core structure according to the present invention;

FIG. 4 is a schematic view showing the connection relationship between the polypropylene film, the electrical aluminum foil and the hollow mandrel bar according to the present invention;

FIG. 5 is a schematic view of the assembly of the polypropylene film and the electrical aluminum foil of the present invention;

FIG. 6 is a schematic view of a process flow for manufacturing the present invention.

In the figure: 1. a top insulated terminal; 2. a housing; 3. an upper cover; 4. a capacitor core package; 5. a ground terminal; 6. assembling a base; 7. an overpressure damping device; 8. an electrician round paperboard; 9. a metal curved pad; 10. an insulating filling layer; 11. a lower capacitor core; 12. a capacitor core is arranged; 13. mounting a positioning sleeve; 14. a lower positioning sleeve; 15. supporting the round electrical paper board; 16. an upper fixing resin plate; 17. an upper positioning ring; 18. a middle positioning ring 18; 19. a lower positioning ring; 20. a pressure isolation device; 21. a flexible cable; 22. a high voltage insulating bushing; 23. connecting the copper bars; 24. an insulating protective sleeve; 25. a polypropylene film; 26. an electrical aluminum foil; 27. a hollow core rod; 28. discharging the foil; 29. reserving edges; 30. and (5) reserving edges.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-6, an embodiment of the present invention is shown: the utility model provides a capacitor for damping absorption circuit of high voltage direct current transmission converter valve, including top insulation terminal 1, shell 2, upper cover 3, electric capacity core package 4, ground terminal 5, 2 inside electric capacity core packages 4 that are provided with of shell, the top of shell 2 is provided with upper cover 3, electric capacity core package 4 top links to each other with top insulation terminal 1, thereby electric capacity core package 4 top links to each other with ground terminal 5 and realizes the equipotential connection with the shell, top insulation terminal 1 is equipped with assembly base 6 and sealing washer with the upper and lower end cooperation department of upper cover 3, electric capacity core package 4 bottom is equipped with electrician's circle cardboard 8 and metal curved surface pad 9, be used for internal insulation and core package fixed action, the surface of shell 2 is provided with over-pressure buffer 7.

In this implementation, the capacitor core package 4 includes a lower capacitor core 11, an upper capacitor core 12, an upper locating sleeve 13, a lower locating sleeve 14, a supporting circular electrical paper board 15, an upper fixing resin plate 16, an upper locating ring 17, a middle locating ring 18, a lower locating ring 19, a pressure isolating device 20, a flexible cable 21, a high-voltage insulating sleeve 22, a connecting copper bar 23 and an insulating protective sleeve 24, the lower capacitor core 11 and the upper capacitor core 12 are arranged inside the insulating protective sleeve 24, the lower capacitor core 11 and the upper capacitor core 12 are connected in series through the connecting copper bar 23, the lower capacitor core 11 and the upper capacitor core 12 are fixed through the supporting circular electrical paper board 15, the upper fixing resin plate 16, the upper locating ring 17, the middle locating ring 18 and the lower locating ring 19, and reliable connection between the two cores is ensured;

the lower capacitor core 11 is connected with the pressure isolating device 20 and the upper capacitor core 12 is connected with the flexible cable 21 by a tin soldering mode, the pressure isolating device 20 is realized by a pressure buffer groove of the shell and a wire which is specially processed in the shell, the pressure buffer groove can extend to apply pressure to the wire which is specially processed in the shell when the internal pressure of the capacitor is increased, when the pressure is increased to a certain degree, the pressure buffer groove rapidly extends and pops the wire, a certain point of one lead is specially cut and ground, the bearing tension of the lead is set to the tension value required by design, the pressure buffer groove is rolled by the aluminum round shell, when the internal pressure is increased to a certain degree, the notch of the lead is broken when the set pressure is reached, the pressure buffer groove and the shell cover are bulged by more than 30mm due to the internal pressure, namely, the distance between the broken part of the lead and the fracture is kept away from the fracture, thereby avoiding the phenomena of virtual connection and arc drawing of the lead, after the pressure isolating device 20 acts, the capacitor is in an open-circuit state, and the current is cut off to be separated from the power supply;

in the prior art, an insulating terminal made of ceramic materials is generally welded with an upper cover in a tin soldering mode, and is welded with a leading-out guide rod in a silver tin soldering mode, ceramics can be welded to a metal cover and a metal terminal after being back-silvered, because of the process problem caused by the contact of a silver layer and the ceramics, insufficient welding is often generated to be easy to separate and cause leakage of the terminal part, in addition, the selected ceramic porcelain bushing has small volume and is easy to crack or even explode due to thermal expansion and the like during welding, particularly, the crack is not obvious, and potential safety hazards exist when the terminal is applied to a field, in the invention, an assembly base 6 and a sealing ring are arranged at the matching part of the upper end and the lower end of the top insulating terminal 1 and the upper cover, the sealing ring is sealed by using the sealing rings made of different materials (such as silica gel materials) through an assembly type structure, the sealing performance of a product can be effectively ensured, and leakage of internal gas can not occur, thereby ensuring the performance of the electric box of the capacitor.

The bottom of the lower capacitor core 11 is provided with a lower locating sleeve 14, the top of the upper capacitor core 12 is provided with an upper locating sleeve 13, and the cores are kept insulated through the bottom end and the top end by the locating sleeves, the multiple cores of the capacitor for the traditional high-voltage direct-current transmission converter valve damping absorption loop are generally welded by adopting conducting wires, the cores are not fixedly located, the bottom and the top end of each core are wrapped by multiple electrical insulating paper to keep insulated, the inner capacitor cores are fixed through locating rings, the locating rings can effectively ensure that the two cores are concentrically fixed without deviation, the cores are soldered by U-shaped copper foils, the requirements of electrical connection and low inductance can be effectively ensured, the bottom end and the top end of each capacitor core are kept insulated through the locating sleeves, stepped structures for increasing friction force are arranged in the locating sleeves, the cores can be effectively ensured not to be displaced, and the outer edges of the locating sleeves are provided with flanging structures, can be reliably clamped with the aluminum shell.

The outer surface of the pressure isolation device 20 is sleeved with a high-voltage insulating sleeve 22, and the pressure isolation device 20 ensures insulating performance through the high-voltage insulating sleeve 22.

In this embodiment, the lower capacitor core 11 and the upper capacitor core 12 include a polypropylene film 25, an electrical aluminum foil 26, a hollow core rod 27 and a polypropylene film 25, the polypropylene film 25 and the electrical aluminum foil 26 are combined with each other in a laminated manner and wound around the outer surface of the hollow core rod 27, the wound capacitor is wound in a spiral shape by separating two layers of plates and two layers of media, and is generally classified into two winding methods, a general winding method and a non-inductive winding method according to the lead-out manner, and the foil type electrode generally adopts the non-inductive winding method, and calculates the amount of wound capacitor by referring to a parallel plate core. Any metal plate achieves the effect of forming the polar plates of two capacitors after being wound, and when the metal plate is unfolded into a strip-shaped flat plate structure, only two stages of media form the capacity, so that compared with the capacity obtained by a capacitor core which has the same polar plate area and is unfolded into a flat plate structure, the capacity obtained after the winding link is doubled, the size of the capacitor is greatly reduced due to the favorable factors, and the capacitor is particularly suitable for single-machine automatic winding, the traditional foil type winding usually adopts a three-roll aluminum foil winding structure (two) inner series type structure, although the voltage of the margin 29 of the aluminum foil and the thin film can be reduced to half of the rated voltage, the voltage between two aluminum foils on the same layer is equal to the rated voltage, and therefore the middle margin 30 between the two aluminum foils on the same layer is a weak link of the voltage resistance of the capacitor.

In the implementation, the top insulating terminal 1 and the assembly base 6 are made of modified PBT materials, and the modified PBT materials are adopted, compared with ceramic materials used in the prior art, the ceramic has no plastic deformation at normal temperature, and has large compressive strength and smaller tensile strength, bending strength and impact strength, the theoretical strength of the ceramic is very high according to the proportion of the materials, but the actual strength of the ceramic is only about 1% of the theoretical strength, the ceramic is subjected to the processing environment, the sintering process and other factors, and the performance stability is not easy to maintain, and after the PBT high polymer material and the glass fiber reinforced material are compositely modified, the strength is high, the fatigue resistance is realized, the size is stable, and the creep deformation at high temperature is extremely small; the heat aging resistance and the solvent resistance are good; the insulating property is excellent (the electrical property can be kept stable even under the conditions of humidity and high temperature, and the insulating material is an ideal material for manufacturing electronic and electrical parts); arc resistance: 120 s; has excellent forming and processing characteristics.

In this embodiment, the capacitor for the damping absorption loop of the early hvdc valve for high voltage direct current transmission is usually impregnated with Mineral Oil (MO), diarylethane (PXE/PEPE) and the like by filling an insulating filling layer 10 formed by sulfur hexafluoride and nitrogen mixed insulating gas between the capacitor core package 4 and the electrical round paper board 8 and the metal curved pad 9 in vacuum, and the foil-type impregnation process cannot meet the requirement of gradually being replaced by a dry-type metallization structure along with the requirement of no oil in the power grid, but the dry-type metallization structure has a large partial discharge effect because the impregnation treatment is not performed, that is, only a partial region in the insulator is subjected to discharge, but the partial discharge does not penetrate between the conductors to which voltage is applied, and can occur near the conductors or in other places, and the phenomenon is called as partial discharge. Each time, the local discharge has some influence on an insulating medium, the slight local discharge has small influence on the insulation of the power equipment, and the reduction of the insulation strength is slow; the strong partial discharge can cause the insulation strength to be reduced quickly, which is an important reason causing the insulation breakdown of high-voltage electrical equipment finally and also an important sign of insulation degradation, the evaporation method adopted by the traditional metallized electrode has high requirements on a base material, particularly a metal film with a bright surface is required to be formed, the base material has good surface smoothness, so a polypropylene optical film is required to be used, the optical film means that a impregnant cannot effectively enter between film layers, the impregnation effect is poor, even a plurality of manufacturers directly give up the impregnation link, and the partial discharge phenomenon is serious.

In this implementation, shell 2 adopts aluminium to make and dull polish oxidation treatment, upper cover 3 is equipped with the hole sealing, the surface of shell 2 is provided with over pressure buffer 7, traditional high voltage direct current transmission converter valve damping absorption circuit capacitor adopts plain noodles aluminum hull usually, the aluminum hull is not through the polishing, probably remaining burr, and after the burr is got rid of in the polishing, it produces the light interference easily to form the mirror surface effect, influence on-the-spot inspection and examine etc., on the basis of traditional shell polishing, dull polish treatment has been done, the surface is more fine and smooth soft, the outward appearance of product has been guaranteed promptly, can not produce the light interference again, and the dull polish material is taken conveniently, corrosion-resistant effect is good.

In the implementation, the electrical aluminum foil 26 and the polypropylene film 25 are staggered to enable the electrical aluminum foil 26 to protrude to form a foil 28, the electrical aluminum foil 26 and the polypropylene film 25 are staggered to enable the electrical aluminum foil 26 to stretch to form a reserved edge 29, a middle reserved edge 30 is formed between the electrical aluminum foils 26, a three-inner-string structure composed of four aluminum foils or a four-inner-string structure composed of five aluminum foils is adopted, in the three-inner-string structure, the voltage of the reserved edge 29 of the aluminum foils and the film can be reduced to 1/3 of a rated voltage, the voltage of the middle reserved edge 30 between the two aluminum foils on the same layer is equal to the rated voltage 1/2, and the voltage-resistant level of the middle reserved edge 30 of the three-inner-string is doubled compared with that of the (two) inner-string structure; in the four-inner-string structure, the voltage of the reserved edge 29 of the aluminum foil and the film can be reduced to 1/4 of the rated voltage, and the voltage of the reserved edge 30 between two aluminum foils on the same layer is equal to 1/3 of the rated voltage, so that the withstand voltage level of the reserved edge 30 of the four-inner-string structure is improved by two times compared with that of the (two) inner-string structure.

In the implementation, the polypropylene film 25 is designed to be coarsened on both sides, the polypropylene film is coarsened on both sides, the impregnation effect is excellent through the gaps between the film layers and the capillary action, the gaps between the film layers are filled with benzyl toluene (M/DBT) which is an impregnant with excellent electrical performance, the partial discharge phenomenon is greatly reduced, the mixture of the benzyl toluene and the dibenzyl toluene, namely the benzyl toluene (M/DBT), is an excellent impregnant for the power capacitor, the impregnant can be widely applied to the power industry, the low-temperature partial discharge performance is excellent, the working field strength is high, the electrical insulation performance is obviously superior to Mineral Oil (MO) and diarylethane (PXE/PEPE), the oil is called as a novel capacitor oil of the third generation in the world, because the impregnation is processed under high vacuum (1 Pa), the insulation oil is completely filled between the polypropylene film layers of the coarsened film, the impregnating agent can not come out from between the film layers under normal pressure, so that the impregnated capacitor core still has the excellent electrical performance of the impregnated capacitor after the redundant external insulating oil is removed, and then sulfur hexafluoride and nitrogen mixed insulating gas is used for filling, so that on one hand, the impregnation ensures the electrical performance of the capacitor core, on the other hand, the mixed insulating gas ensures the electrical insulating performance outside the core, and the commonly adopted mixed insulating gas consists of 90% of nitrogen and 10% of sulfur hexafluoride, and formally combines related documents and tests, 90% of nitrogen and 10% of sulfur hexafluoride have the insulating performance which is nearly equal to pure sulfur hexafluoride, so that the cost can be effectively reduced, the energy is saved, and the oil and gas injection process after the impregnation of the capacitor can completely meet the related test standard requirements through a complete type test.

In this embodiment, the electrical aluminum foil 26 has a thickness of 5 μm, and has good processability and overcurrent capacity.

In this embodiment, the insulating protection sheath 24 is made of polyester material, so as to ensure the insulating property of the whole core package.

The invention is further described with reference to the accompanying drawings in which:

as shown in fig. 1, the capacitor for the damping absorption loop of the high-voltage direct-current transmission converter valve comprises a top insulating terminal 1, a shell 2, an upper cover 3, a capacitor core package 4 and a grounding terminal 5, wherein the bottom end of the capacitor core package 4 is connected with the top insulating terminal 1, the top end of the capacitor core package 4 is connected with the grounding terminal 5 so as to realize equipotential connection with the shell, and an assembly base 6 and a sealing ring are arranged at the matching position of the top insulating terminal 1 and the upper end and the lower end of the upper cover 3. And sealing rings are arranged at the matching positions of the grounding terminal 5 and the upper end and the lower end of the upper cover 3. Top insulation terminal 1 adopts modified PBT (polybutylene terephthalate) material with assembly base 6, shell 2 realizes overpressure buffer 7 through the roll extrusion, reach the effect that overpressure extends, 4 bottoms of electric capacity core package are equipped with electrician's circle cardboard 8 and metal curved surface pad 9, be used for internal insulation and core package fixed action, electric capacity core package 4 and electrician circle cardboard 8, fill behind the vacuum between the metal curved surface pad 9 with sulfur hexafluoride and nitrogen gas mixed insulating gas 10, shell 2 adopts aluminium to make and dull polish oxidation treatment, be equipped with the hole sealing at upper cover 3.

As shown in fig. 2, the capacitor core package 4 includes a lower capacitor core 11, an upper capacitor core 12, an upper positioning sleeve 13, a lower positioning sleeve 14, a supporting round electrical paper board 15, an upper fixing resin plate 16, an upper positioning ring 17, a middle positioning ring 18, a lower positioning ring 19, a pressure isolation device 20, a flexible cable 21, a high-voltage insulating sleeve 22, a connecting copper bar 23, and an insulating protective sheath 24. The lower capacitor core 11 and the upper capacitor core 12 are connected in series through a connecting copper bar 23, the lower capacitor core 11 is connected with a pressure isolation device 20 and the upper capacitor core 12 is connected with a flexible cable 21 in a lead-free soldering tin mode, the lower capacitor core 11 and the upper capacitor core 12 are fixed through a supporting round electrical paper board 15, an upper fixing resin plate 16, an upper positioning ring 17, a middle positioning ring 18 and a lower positioning ring 19 to ensure the reliable connection between the two cores, the lower capacitor core 11 and the upper capacitor core 12 ensure the insulation performance of the upper end and the lower end through an upper positioning sleeve 13 and a lower positioning sleeve 14, the pressure isolation device 20 ensures the insulation performance through a high-voltage insulation sleeve 22, and an insulation protective sleeve 24 is made of polyester to ensure the insulation performance of the whole core package.

As shown in fig. 3-5, the capacitor core comprises a polypropylene film 25, an electrical aluminum foil 26, and a hollow core rod 27. The polypropylene film 25 and the electrical aluminum foil 26 are wound on the hollow mandrel 27 through non-inductive winding so as to be rolled to a required capacity, the electrical aluminum foil 26 and the polypropylene film 25 protrude to form an outlet foil 28 through dislocation, the electrical aluminum foil 26 and the polypropylene film 25 extend to form a reserved edge 29 through dislocation, and the two electrical aluminum foils 26 are separated from each other through dislocation so as to form a reserved edge 30.

The outgoing foil 28 is an electric connection circuit of the capacitor core, the reserved edge 29 is the insulation performance of the capacitor core, and the middle reserved edge 30 is a multi-inner-series process, so that the high-voltage resistance characteristic is realized.

The polypropylene film 25 is designed to be coarsened on two sides, so that the impregnation effect is ensured, and the electrical performance is enhanced.

The electrical aluminum foil 26 has a thickness of 5 μm and has good processability and overcurrent capacity.

The capacitor core is of a full-film foil structure, and has no capacity attenuation and no self-healing failure characteristic.

As shown in fig. 6, the process flow of the capacitor for the damping absorption loop of the high-voltage direct-current transmission converter valve comprises the core processes of material slitting, element winding, tin coating and welding wire welding, element shaping, product assembling, product edge sealing, deoiling and gas injection, cleaning, packaging, warehousing and the like.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or scope of the present invention. Accordingly, the embodiments of the invention are exemplary, but not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

In the description of the present invention, "a plurality" means two or more unless otherwise specified; the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.