A non-metallic shell flexible capacitor for power grid

Abstract

This invention discloses a non-metallic shell flexible DC capacitor for power grids, relating to the field of capacitor technology. It includes a shell and a core assembly installed within the shell. The shell includes a top plate, a bottom plate, and several vertically arranged side plates. Adjacent side plates are vertically connected, and horizontal reinforcing ribs are provided between adjacent side plates. The shell is made of polyetheretherketone carbon fiber composite material. This invention addresses the problem of metal flexible DC capacitors, which suffer from heavy metal shells, making transportation and installation difficult, especially at heights where the supporting components bear significant weight, leading to a short installation lifespan.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, and more specifically, to a flexible DC capacitor with a non-metallic casing for use in power grids. Background Technology

[0002] Flexible DC transmission is an important piece of equipment for building smart grids. Compared with traditional methods, flexible DC transmission has strong technical advantages in areas such as isolated power supply, capacity expansion and upgrading of urban distribution networks, AC system interconnection, and large-scale wind farm grid connection. It is a strategic choice to change the development pattern of large power grids.

[0003] The flexible DC capacitors used in existing power grids have a large number of internal cores due to their large current and voltage, resulting in an increased size. In order to accommodate and protect these cores, a large outer casing is required. Existing casings, considering issues such as sealing, heat dissipation, and robustness, mostly use metal casings. Combined with the large number of cores, this results in the overall weight of existing flexible DC capacitors being large, making transportation and installation troublesome, especially for installations at high altitudes. When suspended at high altitudes for extended periods, high-quality support components are required.

[0004] Furthermore, existing flexible DC capacitors generally use metal casings (such as aluminum alloys and stainless steel), which have the following fatal flaws:

[0005] Heavy weight: The metal casing accounts for 20%-30% of the total weight of the capacitor, increasing transportation and installation costs (such as the difficulty of hoisting offshore wind power platforms).

[0006] Susceptible to corrosion: In coastal, humid or high salt spray environments, the metal casing is prone to rusting, which leads to a decrease in the strength of the casing and moisture absorption of internal components (such as deterioration of the core insulation performance).

[0007] Electromagnetic interference: The metal casing can reflect or shield electromagnetic waves, which may affect the normal operation of surrounding communication equipment or sensors.

[0008] High processing costs: Complex-shaped metal shells need to be manufactured through processes such as casting and machining, which are time-consuming and costly.

[0009] Insulation requires additional processing: The metal casing itself is conductive, so an insulating layer (such as epoxy board) needs to be added between the casing and the internal components, which increases the structural complexity. Summary of the Invention

[0010] This invention provides a non-metallic shell flexible DC capacitor for power grids, addressing the challenges of transporting and securing the heavy metal shells of flexible DC capacitors during installation. In particular, flexible DC capacitors used in power grids are typically installed at high locations, placing significant stress on their supporting components, which can easily reduce the overall lifespan of the capacitor.

[0011] To achieve the above object, the present invention provides the following solutions:

[0012] A flexible DC capacitor with a non-metallic casing for power grids includes a casing and a core assembly installed inside the casing. The casing includes a top plate, a bottom plate, and several vertically arranged side plates. Adjacent side plates are vertically connected, and horizontal reinforcing ribs are provided between adjacent side plates. The casing is made of polyetheretherketone carbon fiber composite material.

[0013] This invention strengthens the shell by vertically connecting two adjacent side plates and setting reinforcing ribs, while reducing the thickness of a single side plate, thereby reducing the weight of the entire shell. The shell is made of polyetheretherketone carbon fiber composite material, which is lightweight and strong, solving the problem of heavy metal shells. This reduces the overall weight of the capacitor, simplifies installation, and reduces the load on the support components when installed at a high position.

[0014] Polyetheretherketone (PEEK) carbon fiber composite material has a density only 1 / 4 to 1 / 5 that of a metal shell, enabling an overall weight reduction of over 40% for capacitors, thus lowering the load-bearing requirements of power grid towers. Its tensile strength is increased by 100% (at room temperature) to 300% (at 150°C), and its heat distortion temperature is greater than 300°C, meeting the high-temperature operating conditions of flexible DC systems. Its volume resistivity is >10 Ω·cm. 16 With a strength of Ω·cm, it exhibits superior acid and alkali resistance compared to metals, preventing shell degradation caused by electrolytic corrosion.

[0015] Furthermore, the core assembly includes a busbar, several busbars connected to the busbar, and capacitor cores mounted on the busbars. Several limiting plates are provided on the outer side of the busbars, and the limiting plates are mounted on the reinforcing ribs.

[0016] Due to the vertical connection between two adjacent side plates and the structural feature of having reinforcing ribs, by setting a limiting plate on the outside of the busbar and placing the limiting plate on the reinforcing rib, not only are the characteristics of the device shell combined, making the device structure more compact and reasonable, but the load-bearing capacity of the busbar is also enhanced, and the impact resistance of the device is improved.

[0017] Furthermore, the capacitor core includes a large core and a small core for filling the gaps between the large cores.

[0018] By filling the gaps between large cores with small cores, the space utilization within the casing is improved. The staggered arrangement of large and small cores makes the gaps between the cores more uniform, forming a honeycomb structure, reducing ineffective space, and reducing the volume by 15% for the same capacity. The staggered arrangement increases the airflow channels between the cores (the longitudinal gap increases by 50%). Combined with the thermally conductive and insulating coating of the non-metallic casing (boron nitride coating, which increases the thermal conductivity by 30 times), the core temperature rise is reduced by 13°C, extending the lifespan by 5-8 years. Furthermore, with the same capacitor capacity, the improved space utilization means that the overall volume of the capacitor will be reduced, and the casing and internal connecting parts will also be reduced accordingly, thereby reducing the overall weight of the capacitor.

[0019] Furthermore, the busbar includes a connecting section connected to the capacitor core and a vibration damping section connecting two adjacent connecting sections, the vibration damping section being configured with a corrugated structure.

[0020] The corrugated structure of the damping section enables the busbar to have a certain degree of elasticity, providing some displacement compensation for the capacitor core and solving the stress concentration problem of traditional rigid copper busbars.

[0021] Furthermore, the vibration damping section has a honeycomb-shaped hollow area.

[0022] By designing the vibration damping section as a honeycomb-shaped hollow structure, not only can the weight of the busbar be reduced, but the charge along the longitudinal end edge can also be dispersed.

[0023] Furthermore, the limiting plate is disposed on the vibration damping section.

[0024] The vibration damping section is divided into upper and lower sections by a limiting plate. The upper section is used to support the capacitor core installed on the upper connecting section and to buffer the impact force borne by the upper capacitor core. The remaining impact force is then released to the reinforcing ribs and the housing through the limiting plate. The lower section is used to pull the capacitor core installed on the lower connecting section and to buffer the impact force borne by the lower capacitor core. Similarly, the remaining impact force is released to the reinforcing ribs and the housing through the limiting plate, thereby enhancing the overall impact resistance of the capacitor core.

[0025] Furthermore, the top plate and bottom plate are connected to the side plates in a detachable manner, as are the side plates to each other.

[0026] The modular design allows for the addition or removal of side plates according to actual needs, enabling flexible adjustment of capacitor capacity and expanding the applicable range of the capacitor.

[0027] Furthermore, the detachable connection joints are equipped with a sealing structure, employing a press-fit seal. A press-fit unit and a sealing element are installed at the module connection. The press-fit unit secures two or more components together, while the sealing element prevents leakage at the connection. During the press-fit process, pressure is applied to deform the rivets, thus firmly fixing the connected parts together. Simultaneously, the sealing element is compressed or extruded, filling the gaps at the connection to achieve a seal. Through the design of a sealing fluid or elastic sealing ring, the press-fit seal structure can provide a reliable seal while connecting. The press-fit process provides higher connection strength than traditional bolt connections. Because the press-fit seal structure can complete connection and sealing in a single operation, it greatly simplifies the module splicing and assembly process, improving installation efficiency.

[0028] Furthermore, a transverse groove is provided on the inner wall of the side plate, and the reinforcing rib is installed by embedding it in the groove.

[0029] By embedding the reinforcing ribs laterally into the grooves, the load-bearing capacity of the reinforcing ribs is enhanced, and the installed reinforcing ribs can also better connect the two adjacent side plates, enhancing the connection strength of the side plates.

[0030] Furthermore, the upper surface of the reinforcing rib is provided with an insulating elastic element.

[0031] The insulating elastic element isolates the casing from the busbar, while further providing a buffer for the capacitor core, reducing the impact force it withstands and extending the service life of the device; the volume insulation resistance of the insulating elastic element used as an insulator should be 1x10⁻⁶. 13 Ω·cm; Under normal circumstances, a large volume resistivity also indicates a large surface resistivity. The breakdown voltage per unit thickness of an insulating elastic component is an indispensable technical parameter for evaluating the electrical insulation performance of insulating rubber products. When the rubber formula and process design are reasonable and the breakdown voltage test is standardized, its breakdown voltage should not be lower than 15KV / mm (AC) and 25KV / mm (DC), ensuring the safety and reliability of insulating rubber products during normal use.

[0032] Furthermore, the inner wall of the housing is provided with an electric field shielding layer, and the outer wall is provided with a thermally conductive and insulating coating.

[0033] An electric field shielding layer can reduce the mutual influence of the internal and external electric fields of a capacitor. It is typically achieved by magnetron sputtering to deposit a 50-100 nm aluminum oxide thin film, with the surface resistivity controlled at 10. 6 -10 8 Within the Ω range, it suppresses high-voltage electric field distortion. The electric field shielding layer has strong insulation performance, which can effectively prevent charge leakage and short circuit, ensure the normal operation and safe use of the capacitor, and extend the service life of the capacitor.

[0034] Thermally conductive and insulating coatings reduce the risk of capacitor leakage, while also enhancing internal heat conduction, improving the lateral heat dissipation efficiency of the casing, reducing the internal temperature of the capacitor, and preventing excessive internal temperature from affecting the capacitor's operation and lifespan. They must simultaneously meet key performance requirements such as thermal conductivity, insulation, and high-temperature resistance to meet the heat dissipation and safety needs of electronic equipment, industrial machinery, and other scenarios. Thermally conductive and insulating coatings effectively isolate electronic components from the external environment, preventing electrical short circuits and leakage, and ensuring the long-term stable operation of electronic components.

[0035] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0036] (1) By vertically connecting two adjacent side plates and setting reinforcing ribs, the present invention strengthens the shell while reducing the thickness of a single side plate, thereby reducing the weight of the entire shell. The shell is made of polyether ether ketone carbon fiber composite material, which is lightweight and strong, solving the problem of heavy metal shells, thereby reducing the overall weight of the capacitor, reducing the installation difficulty, and reducing the load on the support when installed at a high place.

[0037] (2) By setting a limiting plate on the outside of the busbar and placing the limiting plate on the reinforcing rib, not only are the characteristics of the device shell combined, making the device structure more compact and reasonable, but the load-bearing capacity of the busbar is also enhanced, and the impact resistance of the device is improved. Through modular setting, the number of side plates can be increased or decreased according to actual needs, thereby realizing flexible adjustment of capacitor capacity and improving the applicable range of capacitor.

[0038] (3) By filling the gaps between large cores with small cores, the space utilization rate inside the shell is improved. The staggered arrangement between large and small cores makes the gaps between cores more uniform, forming a honeycomb structure, reducing ineffective space, and reducing the volume by 15% for the same capacity. The staggered arrangement increases the airflow channels between cores (the longitudinal gap increases by 50%). Combined with the thermally conductive and insulating coating of the non-metallic shell (boron nitride coating, which increases the thermal conductivity by 30 times), the core temperature rise is reduced by 13°C, and the lifespan is extended by 5 to 8 years. Furthermore, with the same capacitor capacity, the increased space utilization rate means that the overall volume of the capacitor will be reduced, and the shell and internal connecting parts will also be reduced accordingly, thereby reducing the overall weight of the capacitor.

[0039] (4) The damping section is divided into upper and lower sections by the limiting plate. The upper damping section is used to support the capacitor core installed on the upper connecting section and to buffer the impact force borne by the upper capacitor core. The remaining impact force is then released to the reinforcing rib and the shell through the limiting plate. The lower damping section is used to pull the capacitor core installed on the lower connecting section and to buffer the impact force borne by the lower capacitor core. Similarly, the remaining impact force is released to the reinforcing rib and the shell through the limiting plate, thereby enhancing the overall impact resistance of the capacitor core.

[0040] (5) The housing and busbar are isolated by an insulating elastic element, which further provides a buffer force for the capacitor core, reduces the impact force it bears, and enhances the service life of the device; the volume insulation resistance of the insulating elastic element used as an insulator should be 1x10. 13 Ω·cm; Under normal circumstances, a large volume resistivity also indicates a large surface resistivity. The breakdown voltage per unit thickness of an insulating elastic component is an indispensable technical parameter for evaluating the electrical insulation performance of insulating rubber products. When the rubber formula and process design are reasonable and the breakdown voltage test is standardized, its breakdown voltage should not be lower than 15KV / mm (AC) and 25KV / mm (DC) to ensure the safety and reliability of insulating rubber products during normal use.

[0041] (6) The electric field shielding layer can reduce the mutual influence of the electric fields inside and outside the capacitor. It is generally formed by magnetron sputtering to deposit a 50-100 nm aluminum oxide thin film, and the surface resistivity is controlled at 10. 6 -10 8 Within the Ω range, it suppresses high-voltage electric field distortion. The electric field shielding layer has strong insulation performance, effectively preventing charge leakage and short circuits, ensuring the normal operation and safe use of the capacitor, and extending its service life. The thermally conductive insulating coating reduces the risk of leakage and enhances internal heat conduction, improves the lateral heat dissipation efficiency of the casing, and lowers the internal temperature of the capacitor. This prevents the internal temperature from becoming too high, which could affect the operation and service life of the capacitor. It must simultaneously meet key performance requirements such as thermal conductivity, insulation, and high temperature resistance to meet the heat dissipation and safety needs of electronic equipment, industrial machinery, and other scenarios. The thermally conductive insulating coating can effectively isolate electronic components from the external environment, avoid electrical short circuits and leakage, and ensure the long-term stable operation of electronic components. Attached Figure Description

[0042] The accompanying drawings, which are provided to further illustrate embodiments of the invention and constitute a part of this invention, are not intended to limit the scope of the invention.

[0043] Figure 1 This is a cross-sectional view of the non-metallic shell flexible capacitor in this invention;

[0044] Figure 2 This is a schematic diagram of the capacitor core arrangement in this invention;

[0045] Figure 3 This is a schematic diagram of the busbar structure in this invention;

[0046] Among them, 1-side plate, 2-reinforcing rib, 3-busbar, 301-connecting section, 302-vibration damping section, 4-capacitor core, 401-large core, 402-small core, 5-limiting plate. Detailed Implementation

[0047] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other.

[0048] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0049] Example 1

[0050] This embodiment provides a non-metallic housing flexible DC capacitor for power grids, such as... Figures 1-3 As shown, it includes a housing and a core assembly installed in the housing. The housing includes a top plate, a bottom plate and several vertically arranged side plates 1. Adjacent side plates 1 are vertically connected and horizontal reinforcing ribs 2 are provided between adjacent side plates 1. The outer shell is made of polyetheretherketone carbon fiber composite material.

[0051] The individual side panel 1 is a rectangular plate with a height greater than its length and width. It is installed vertically, with adjacent side panels 1 fitting together at their heights to form a right angle from a top view. Reinforcing ribs 2 are placed inside the right angle. This structure significantly enhances the load-bearing capacity in the vertical direction. When the load requirement is met, the thickness of the side panel 1 can be greatly reduced, thus reducing the overall weight of the shell. The number of reinforcing ribs 2 is arbitrary, but preferably two reinforcing ribs 2 are placed inside the right angle formed by every two adjacent side panels 1, respectively... The number of reinforcing ribs 2 is increased on both the upper and lower sides of the side plate 1, and the number increases with the length of the side plate 1. The polyetheretherketone (PEEK) carbon fiber composite material preferably uses a 30% carbon fiber reinforced PEEK matrix, which has comprehensive advantages such as high strength, high modulus, high temperature resistance, and corrosion resistance. Its density is only 1 / 4 to 1 / 5 that of the metal shell, which can achieve an overall weight reduction of more than 40% for the capacitor, reducing the load-bearing requirements of the power grid tower. The tensile strength is increased by 100% (room temperature) to 300% (150℃), and the heat distortion temperature is greater than 300℃, meeting the high-temperature operating conditions of flexible DC systems. The volume resistivity is >10. 16 With a strength of Ω·cm, it exhibits superior acid and alkali resistance compared to metals, preventing shell degradation caused by electrolytic corrosion.

[0052] In a more preferred embodiment, the core assembly includes a busbar, a plurality of busbars 3 connected to the busbar, and capacitor cores 4 mounted on the busbars 3. A plurality of limiting plates 5 are provided on the outer side of the busbars 3, and the limiting plates 5 are mounted on the reinforcing ribs 2.

[0053] Among them, the busbar 3 is installed vertically and is installed on one side of the reinforcing rib 2 inside the housing, so that the limiting plate 5 corresponds to the reinforcing rib 2. Two busbars are provided, located at the top inside the housing, and are respectively connected to the positive terminal and the negative terminal installed at the top of the housing. The number of limiting plates 5 is set according to the actual situation, preferably corresponding one-to-one with the reinforcing rib 2 located inside the housing. The outer surface of the limiting plate 5 is provided with an insulating coating.

[0054] The capacitor core 4 includes a first electrode and a second electrode stacked together. The first electrode includes a first electrode layer and a first base layer, and the second electrode includes a second electrode layer and a second base layer. In the capacitor core 4, the first electrode layer and the second electrode layer serve as the two plates of a capacitor. The first base layer, to which the first electrode layer is attached, is sandwiched between the first electrode layer and the second electrode layer, serving as the dielectric material between the capacitor plates. The second base layer, to which the second electrode layer is attached, is used to prevent the first electrode from contacting the second electrode during winding, thus avoiding a short circuit in the capacitor.

[0055] Before winding the capacitor core 4, only the first electrode and the second electrode need to be stacked, without the need to repeatedly stack the conductive electrodes and insulating film material. The tight connection between the first electrode layer and the first base layer, and between the second electrode layer and the second base layer, further ensures that the film electrodes inside the capacitor core 4 do not misalign during the winding process, thus improving the electrical performance and operational stability of the non-metallic shell flexible DC capacitor for power grids.

[0056] The first electrode layer and / or the second electrode layer can be any metal electrode layer capable of forming electrodes, such as titanium, aluminum, or zinc, or any non-metal electrode layer capable of forming electrodes, such as carbon nanotubes or conductive polymers. The specific materials of the first electrode layer and / or the second electrode layer are determined according to actual needs, and this embodiment does not impose specific limitations. The first base layer and / or the second base layer can be a polypropylene film, a polyester film, or a polyimide film. Preferably, the first base layer and / or the second base layer are high-insulation polypropylene films with a dielectric strength of 800V / μm, a dielectric loss of approximately 0.02%, and a temperature resistance of up to 125℃. Preferably, the thickness of the first base layer and / or the second base layer is 3.4–10μm. The length and width of the first base layer and / or the second base layer are determined according to the actual size requirements of the non-metallic shell flexible capacitor, and this embodiment does not impose specific limitations.

[0057] In a more preferred embodiment, the top plate and bottom plate are detachably connected to the side plate 1, and the side plate 1 is detachably connected to each other.

[0058] The detachable connection preferably adopts a mortise and tenon structure, that is, one of the two adjacent side plates 1 has a groove and the other has a protrusion. The protrusion is embedded into the groove to form a connection. The top plate and bottom plate have mounting grooves on the edges of the side plates 1 running at the top and bottom ends. The upper end of the side plate 1 is embedded into the top plate and the lower end is embedded into the bottom plate to form a closed box structure. Other detachable connection methods can also be used, which will not be elaborated in detail in this application. During installation, according to the overall size of the internal core assembly, select an appropriate number of side plates 1 for splicing, select the corresponding size top plate and bottom plate, install the bottom plate in sequence, put the spliced ​​side plates 1 into the core assembly, and then cover it with the top plate.

[0059] Optionally, the shell can be configured as a modular structure; the side panels 1 are modularized, and since the assembled side panels 1 are continuously spliced ​​together from similar structures, the smallest single unit can be selected as the module, i.e., an L-shaped structure, which is formed by splicing two side panels 1 together, with reinforcing ribs 2 embedded on the inner side of the included angle. The reinforcing ribs 2 can be fixedly connected, such as by welding; the top panel is modularized, and can be multiple cubes or cuboids that can be joined by mortise and tenon joints. The top panel module includes a middle block of the top panel without a groove at the bottom and a top panel with an L-shaped groove. The top plate edge blocks are selected according to the perimeter of the side plates, and the corresponding number of top plate edge blocks and top plate middle blocks are spliced ​​together to form the top plate. The top plate is then fixed using welding, clamps, and other fasteners. The bottom plate is modularized and can be multiple cubes or cuboids that can be connected by mortise and tenon joints. The bottom plate module includes bottom plate middle blocks without grooves at the bottom and bottom plate edge blocks with L-shaped grooves. The corresponding number of bottom plate edge blocks and bottom plate middle blocks are selected according to the perimeter of the side plates, and the bottom plate is spliced ​​together to form the bottom plate. The bottom plate is then fixed using welding, clamps, and other fasteners.

[0060] In addition, to enhance the sealing of the modular housing, a sealing structure is required. If the capacity of the capacitor will not be changed after assembly and installation, it is preferable to assemble the top plate, bottom plate, and side plates and then seal the joints by welding. This provides a good sealing effect and makes the housing more robust. If the capacity of the capacitor will be changed after assembly and installation, it is preferable to install a sealing layer, such as a silicone layer or a rubber layer, in the tenon and mortise joints of the modules.

[0061] For example, a press-fit seal is used, where a press-fit unit and a sealing element are installed at the module connection. The press-fit unit is responsible for fixing two or more parts together, while the sealing element is used to prevent leakage at the connection. During the press-fit process, pressure is applied to deform the rivet, thereby firmly fixing the connected parts together. At the same time, the sealing element is compressed or squeezed out to fill the gap at the connection and achieve a sealing effect. By designing a sealing fluid or elastic sealing ring, the press-fit seal structure can provide a reliable sealing effect while connecting. The press-fit process can provide higher connection strength than traditional bolt connections. Since the press-fit seal structure can complete the connection and sealing in one operation, it greatly simplifies the module splicing and assembly process and improves installation efficiency.

[0062] In a more preferred embodiment, a transverse groove is provided on the inner sidewall of the side plate 1, and the reinforcing rib 2 is embedded in the groove for installation.

[0063] Since the two adjacent side plates 1 are connected in a detachable manner, the reinforcing rib 2 cannot be pre-cast. Therefore, it is also installed in a detachable manner. After the two adjacent side plates 1 are installed, the grooves on the two side plates 1 correspond one-to-one. The reinforcing rib 2 is embedded in the groove. The length of the groove is equal to the length of the side plate 1 to facilitate the embedding of the reinforcing rib 2. The width of the groove is equal to the thickness of the reinforcing rib 2 to make the embedded reinforcing rib 2 secure. Preferably, the reinforcing rib 2 can be fixed by welding after installation to enhance the sealing and strength of the side plate.

[0064] In a more preferred embodiment, the upper surface of the reinforcing rib 2 is provided with an insulating elastic element.

[0065] Because the reinforcing rib 2 contacts the side plate 1 and the limiting plate 5, and the limiting plate 5 is connected to the busbar 3, the capacitor core 4 is directly connected to the shell, requiring isolation. Furthermore, since the capacitor core 4 is easily damaged by external vibrations, it is necessary to reduce the impact force it receives. Therefore, an insulating and elastic material is required, preferably an insulating rubber pad. The volume insulation resistance of the insulating rubber pad used as an insulator should be 1 x 10⁻⁶. 13 Ω·cm; In applications where electrical insulation requirements are not very high, its volume insulation resistance is not less than 1x10 Ω·cm. 10 Ω·cm, under normal circumstances, a large volume resistivity also means a large surface resistivity. The breakdown voltage per unit thickness of rubber insulator is an indispensable technical parameter for measuring the electrical insulation performance of insulating rubber products. When the rubber formula and process design are reasonable and the breakdown voltage test is standardized, its breakdown voltage is not lower than 15KV / mm (AC) and 25KV / mm (DC), ensuring the safety and reliability of insulating rubber products during normal use.

[0066] In a more preferred embodiment, the inner wall of the housing is provided with an electric field shielding layer, and the outer wall is provided with a thermally conductive and insulating coating.

[0067] The electric field shielding layer is formed by embedding a nano-alumina coating on the inner wall of side plate 1. This is typically achieved by magnetron sputtering to deposit a 50-100 nm alumina thin film, with the surface resistivity controlled at 10⁻⁶. 6 -10 8Within the Ω range, it suppresses high-voltage electric field distortion; composite materials, such as polyphenylene sulfide (PPS), can also be used. As a high-performance material, PPS is widely used in capacitor casings. A capacitor is a device that stores charge and releases energy, and its casing plays an important role in protecting the internal components. PPS material has excellent comprehensive properties, making it an ideal material for capacitor casings. PPS material has high reliability and heat resistance. As an important component of electronic devices, capacitors need to withstand long-term operation and harsh environmental conditions. PPS material has high heat resistance and chemical stability, enabling it to work stably for a long time under harsh conditions such as high temperature and high humidity, and is not easily corroded or damaged, ensuring the long-term reliability and stability of capacitors. PPS material also has excellent flame retardant properties. As a critical component in electronic devices, the safety of capacitors is paramount. PPS material possesses self-extinguishing properties at high temperatures, effectively suppressing flame spread and preventing combustion, thus enhancing capacitor safety. PPS material also exhibits excellent electrical insulation properties. Since capacitors typically have high electric field strength, their casings require superior insulation to prevent charge leakage and short circuits, ensuring normal operation and safe use. Furthermore, PPS material possesses good mechanical properties and corrosion resistance. Modified PPS material exhibits excellent mechanical strength and rigidity, effectively resisting external forces and maintaining capacitor stability. Simultaneously, PPS material demonstrates good corrosion resistance, resisting the erosion of acids, alkalis, and other chemicals, extending the capacitor's lifespan.

[0068] The thermally conductive insulating coating must simultaneously meet key performance requirements such as thermal conductivity, insulation, and high-temperature resistance to meet the heat dissipation and safety needs of electronic equipment, industrial machinery, and other scenarios. Preferably, a boron nitride thermally conductive insulating coating is sprayed onto the outer wall of side plate 1. Its thermal conductivity is approximately 30-40 W / (m·K), which is more than three times that of aluminum and more than twice that of copper. This characteristic makes boron nitride thermally conductive insulating sheets of significant application value in the heat dissipation design of high-power electronic devices. Furthermore, its high insulation strength and high insulation resistance effectively isolate electronic devices from the external environment, preventing electrical short circuits and leakage problems. Boron nitride is also a high-temperature stable material with a melting point of over 3000°C, allowing it to operate stably for extended periods in high-temperature environments. Therefore, boron nitride thermally conductive and insulating coatings can maintain their thermal conductivity and insulation properties under high-temperature conditions. Simultaneously, these coatings exhibit excellent corrosion resistance, resisting the erosion of acids, alkalis, solvents, and other chemicals, ensuring the long-term stable operation of electronic components. Furthermore, they have a low density, with a specific gravity of approximately 2.3 g / cm³, making them lighter than aluminum, thus reducing the weight of electronic devices and improving their portability and reliability.

[0069] In a more preferred embodiment, the capacitor core 4 includes a large core 401 and small cores 402 for filling the gaps between the large cores 401. The large core 401 is formed by winding a third electrode and a fourth electrode stacked together; the small core 402 is formed by winding a fifth electrode and a sixth electrode stacked together. The third electrode, the fourth electrode, the fifth electrode, and the sixth electrode include an electrode layer and a base layer of the same material.

[0070] The large core 401 and the small core 402 are arranged in a staggered topology. For example, the size of the large core 401 is φ120mm×300mm, and the size of the small core 402 is φ80mm×300mm. The large core 401 is arranged in a 4×4 matrix with adjacent rows / columns offset by 60mm (1 / 2 of the radius of the large core), forming a honeycomb hexagonal cavity. The edge gaps are filled with small cores 402, eliminating the rectangular dead corners of the traditional neat arrangement. The space utilization rate reaches 92%, which is more than 7% higher than the traditional matrix arrangement, thereby reducing the volume of the non-metallic shell flexible DC capacitor for power grid after installation.

[0071] Example 2

[0072] Based on Example 1, such as Figures 1-3 As shown, the busbar 3 includes a connecting section 301 connected to the capacitor core 4 and a vibration damping section 302 connecting two adjacent connecting sections 301. The vibration damping section 302 is designed with a corrugated structure.

[0073] The number and position of the connecting section 301 correspond one-to-one with the capacitor core 4. The length of the vibration damping section 302 is determined by the spacing between two adjacent capacitor cores 4. Preferably, a vibration damping section 302 is provided at the bottom of the busbar 3 and connected to the bottom plate of the outer casing. An insulating gasket is provided at the connection point. The length of the connecting section 301 is slightly larger than the diameter of the installed capacitor core 4. Vibration damping sections 302 are provided in the remaining parts. Therefore, the busbar 3 with large cores 401 has a longer connecting section 301 and a shorter vibration damping section 302. The busbar 3 with small cores 402 has a shorter connecting section 301 and a longer vibration damping section 302.

[0074] In a more preferred embodiment, the vibration damping section 302 has a honeycomb-shaped hollow area.

[0075] The honeycomb-shaped hollow area is preferably composed of several regular hexagonal holes, which can be evenly distributed on the vibration damping section 302, or can be set only on one or both sides of the vibration damping section 302. Without affecting the strength of the vibration damping section 302, it can effectively improve its elasticity and reduce its weight.

[0076] In a more preferred embodiment, the limiting plate 5 is disposed on the vibration damping section 302. Preferably, it is disposed in the middle of the vibration damping section 302, that is, the vibration damping sections 302 on the upper and lower sides of the limiting plate 5 are of equal length, which can provide the same elastic force to the two capacitor cores 4 on the upper and lower sides of the limiting plate 5, and avoid uneven force on the upper and lower sides of the limiting plate 5. The limiting plate divides the vibration damping section into upper and lower sections. The upper vibration damping section is used to support the capacitor core installed on the upper connecting section, and the impact force borne by the upper capacitor core is buffered by the upper vibration damping section, and the remaining impact force is released to the reinforcing rib and the shell through the limiting plate. The lower vibration damping section is used to pull the capacitor core installed on the lower connecting section, and the impact force borne by the lower capacitor core is buffered by the lower vibration damping section, and the remaining impact force is also released to the reinforcing rib and the shell through the limiting plate, thereby enhancing the overall impact resistance of the capacitor core.

[0077] Example 3

[0078] Based on any of the above embodiments, the following installation steps are included;

[0079] S1. Confirm the overall size of the capacitor and select a base plate of the appropriate size;

[0080] S2. Splice all side panels 1 in pairs into an L-shaped structure and install reinforcing ribs 2;

[0081] S3. Install the L-shaped structure onto the base plate to form an enclosed structure, and install reinforcing ribs 2 between two adjacent L-shaped structures;

[0082] S4. Install the core assembly into the housing, select a top plate of the appropriate size, cover the top plate, and complete the corresponding electrical connections.

[0083] In a more preferred embodiment, the base plate selected in step S1 can be a whole cast according to the overall size of the capacitor, or it can be a structure assembled from modules, which is a base plate module. It can be multiple cubes or cuboids that can be connected by mortise and tenon joints. The base plate module includes a base plate middle block without a groove at the bottom and a base plate edge block with an L-shaped groove. According to the perimeter of the side plate, the corresponding number of base plate edge blocks and base plate middle blocks are selected and assembled into a base plate. The base plate is fixed by welding, clamps and other fasteners.

[0084] In a more preferred embodiment, the core assembly in step S4 is installed as follows: two busbars 3 are selected and placed in a manner where connecting section 301 corresponds to connecting section 301 and vibration damping section 302 corresponds to vibration damping section 302. The two ends of the large core 401 are welded to the corresponding connecting sections 301 of the two busbars 3 to form a large core module. Similarly, two other busbars 3 are selected, and the small core 402 is also welded to the corresponding connecting sections 301 of the two busbars 3 to form a small core module. The large core module is then placed into the housing, and the limiting plate 5 is placed on the reinforcing rib 2. The small core module is placed next to the large core module, and the limiting plate 5 is also placed on the reinforcing rib 2. Then, the large core module and the small core module are placed in sequence until the housing is full. Finally, the large core module and the small core module are connected to the busbar.

[0085] In a more preferred embodiment, the top plate selected in step S4 can be a whole cast according to the overall size of the capacitor, or it can be a structure assembled from modules, which is a top plate module. It can be multiple cubes or cuboids that can be connected by mortise and tenon joints. The top plate module includes a top plate middle block without a groove at the bottom and a top plate edge block with an L-shaped groove. According to the perimeter of the side plate, the corresponding number of top plate edge blocks and top plate middle blocks are selected and assembled into a top plate. The top plate is fixed by welding, clamps and other fasteners.

[0086] Although preferred embodiments of the present invention have been described in detail herein, those skilled in the art, upon understanding the basic inventive concept of the present invention, can make other changes and modifications to these embodiments without departing from the technical concept and core idea of ​​the present invention. Therefore, the appended claims should be interpreted as covering not only the preferred embodiments but also all changes and modifications falling within the scope of the present invention.

[0087] Obviously, based on the technical principles and innovations of this invention, those skilled in the art can make various reasonable modifications and variations to it during the implementation of this invention, and these modifications and variations do not exceed the spirit and scope of this invention. In other words, any modifications and variations made within the scope of the claims of this invention and their equivalents should be considered as part of this invention. Therefore, the scope of protection of this invention is not limited to the specifically described embodiments, but should also include all technically feasible changes and adjustments, as long as these changes and adjustments do not deviate from the basic concept and technical solution of this invention.

Claims

1. A flexible DC capacitor with a non-metallic casing for use in power grids, comprising a casing and a core assembly mounted within the casing, characterized in that, The shell includes a top plate, a bottom plate and several vertically arranged side plates (1), with two adjacent side plates (1) vertically connected and horizontal reinforcing ribs (2) provided between two adjacent side plates (1). The shell is made of polyetheretherketone carbon fiber composite material. The core assembly includes a busbar, several busbars (3) connected to the busbar, and capacitor cores (4) mounted on the busbars (3). Several limiting plates (5) are provided on the outside of the busbars (3), and the limiting plates (5) are mounted on the reinforcing ribs (2). The busbar (3) includes a connecting section (301) connected to the capacitor core (4) and a vibration damping section (302) connecting two adjacent connecting sections (301), wherein the vibration damping section (302) is configured as a corrugated structure; The limiting plate (5) is disposed on the vibration damping section (302).

2. A flexible DC capacitor with a non-metallic casing for power grids according to claim 1, characterized in that, The capacitor core (4) includes a large core (401) and a small core (402) for filling the gaps between the large cores (401).

3. A flexible DC capacitor with a non-metallic casing for power grids according to claim 1, characterized in that, The vibration damping section (302) has a honeycomb-shaped hollow area.

4. A flexible DC capacitor with a non-metallic casing for power grids according to claim 1, characterized in that, The top plate and bottom plate are connected to the side plate (1) in a detachable manner, as are the side plates (1) and the side plates (1) with each other.

5. A flexible DC capacitor with a non-metallic casing for power grids according to claim 1, characterized in that, A transverse groove is provided on the inner wall of the side plate (1), and the reinforcing rib (2) is installed by embedding it in the groove.

6. A flexible DC capacitor with a non-metallic casing for power grids according to claim 1, characterized in that, The upper surface of the reinforcing rib (2) is provided with an insulating elastic element.

7. A flexible DC capacitor with a non-metallic casing for power grids according to claim 1, characterized in that, The inner wall of the housing is provided with an electric field shielding layer, and the outer wall is provided with a thermally conductive and insulating coating.

Images