A capacitor voltage divider

Abstract

This utility model relates to a capacitive voltage divider. The utility model includes a capacitor core housed within a housing; a top cover mounted on the upper end of the housing, with the high-voltage end of the capacitor core connected to the top cover; a bellows mounted on the top cover; a lower cover mounted on the lower end of the housing; and a lead-out sleeve mounted on the lower cover, through which the medium-voltage and low-voltage ends of the capacitor core are led out, enabling connection to an electromagnetic unit. It features small size, light weight, high specific characteristics, excellent electrical performance, fully sealed maintenance-free operation, and energy efficiency.

Description

Technical Field

[0001] This utility model relates to the field of power measurement technology, and in particular to a capacitor voltage divider. Background Technology

[0002] The basic principle of a capacitive voltage divider is to use the capacitive reactance of a capacitor to divide the voltage. Theoretically, in an AC system, it mainly consumes reactive power, with relatively small active power losses (dielectric losses). However, traditional capacitive voltage dividers still have the following problems: Capacitive voltage dividers are typically composed of multiple capacitor core elements connected in series. The dielectric loss tangent of the insulating dielectric material is not ideal, and the accumulated dielectric loss is still relatively large under ultra-high voltage. The structural design of the low-voltage side of the capacitor divider to ground can affect high-frequency characteristics. The stray capacitance of the low-voltage side to ground may exceed the standard, and the high-frequency characteristics will affect the quality of carrier communication. Changes in ambient temperature can affect the voltage division ratio of a capacitor, and the temperature stability of a capacitor (temperature coefficient of capacitance) is related to the stability of voltage signal measurement. Unreasonable structural layout and insulation design often result in capacitor dividers that are large in size, high in cost, and have poor specific characteristics.

[0003] With the increasing demand for high-precision, long-term online monitoring in scenarios such as smart grids and new energy grid connection (e.g., photovoltaic power plants and wind farm booster stations), we continue to develop a capacitor voltage divider with high measurement accuracy, extremely low power consumption, and high bit-rate characteristics. Summary of the Invention

[0004] Therefore, this utility model provides a capacitor voltage divider, which has the characteristics of small size, light weight, high specific characteristics, excellent electrical performance, fully sealed maintenance-free, energy saving and environmental protection.

[0005] To solve the above-mentioned technical problems, this utility model provides a capacitor voltage divider, comprising: shell; The capacitor core is installed inside the housing; The top cover is installed on the upper end of the outer casing, and the high voltage terminal of the capacitor core is connected to the top cover; Corrugated pipe, installed on the upper cover, The lower cover is installed at the lower end of the outer casing; A lead-out sleeve is installed on the lower cover, through which the medium-voltage end and low-voltage end of the capacitor core are led out to connect with the electromagnetic unit.

[0006] In one embodiment of this utility model, sealing gaskets are respectively provided between the upper cover and the upper end of the outer shell, and between the lower cover and the lower end of the outer shell.

[0007] In one embodiment of this utility model, the corrugated pipe includes a corrugated cylinder and an inflation screw and a sealing cap respectively disposed at both ends of the axial direction of the corrugated cylinder, and gas is filled into the inside of the corrugated cylinder through the inflation screw.

[0008] In one embodiment of this utility model, the lead-out sleeve includes an epoxy casting body and a medium-voltage conductive rod and a low-voltage conductive rod disposed on the epoxy casting body; The low-voltage conductive rod is welded to the shielding mesh, and the two ends of the medium-voltage conductive rod are provided with first threaded holes. The first threaded holes are used for the medium-voltage end of the capacitor core to be led out and connected to the inside of the electromagnetic unit. The low-voltage conductive rod has a second threaded hole on its side, which is used to bring out the N terminal of the capacitor core.

[0009] In one embodiment of this utility model, the capacitor core includes several capacitor elements connected in series, clamping plates located at the upper and lower ends of the capacitor elements, and support plates located at the side ends. The capacitor elements are packaged in groups, and each group is isolated from the others by a sealing component and a partition.

[0010] In one embodiment of this utility model, the capacitor core further includes a high-voltage lead, a medium-voltage lead, and a low-voltage lead; the high-voltage lead is equipotentially connected to the upper cover, the low-voltage lead is connected to the low-voltage conductive rod, and the medium-voltage lead is connected to the medium-voltage conductive rod.

[0011] In one embodiment of this utility model, the high-voltage lead, the medium-voltage lead, and the low-voltage lead all include a welded polytetrafluoroethylene (PTFE) wire and a tin-plated copper foil. The tin-plated copper foil is in crimped contact with the capacitor element, and a crimp terminal is welded to one end of the PTFE wire.

[0012] In one embodiment of this utility model, the clamping plates at the upper and lower ends of the capacitor core include an epoxy casting molded body and a plurality of copper screws embedded in the epoxy casting molded body and connected by metal.

[0013] In one embodiment of this utility model, a polypropylene film gasket is provided between the low-voltage end and the ground end of the capacitor core.

[0014] The above-mentioned technical solution of this utility model has the following advantages compared with the prior art: This utility model discloses a capacitive voltage divider, which achieves advantages such as small size, light weight, and high specific characteristics through reasonable selection of main components and optimized structural layout. This capacitive voltage divider has low dielectric loss, stable and excellent electrical performance, long service life, and high resource utilization. Simultaneously, the product adopts a fully sealed structure design, requiring no maintenance, effectively reducing waste, and possessing higher energy-saving and environmental protection value. This capacitive voltage divider features small size, light weight, high specific characteristics, excellent electrical performance, fully sealed maintenance-free operation, and energy saving and environmental protection. Attached Figure Description

[0015] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0016] Figure 1 This is a structural diagram of the capacitor voltage divider of this utility model.

[0017] Figure 2 This is a cross-sectional view of the structure of the capacitor voltage divider of this utility model.

[0018] Figure 3 This is a structural diagram of the corrugated pipe of this utility model.

[0019] Figure 4 This is a structural diagram of the lead-out sleeve of this utility model.

[0020] Figure 5 This is a front view structural diagram of the capacitor core of this utility model.

[0021] Figure 6 This is a side view of the capacitor core of this utility model.

[0022] Figure 7 This is a structural diagram of the clamping plate of this utility model.

[0023] Figure 8 This is an electrical structure diagram of the capacitor core of this utility model.

[0024] Explanation of reference numerals in the instruction manual: 1. Top cover; 2. Sealing gasket; 3. Corrugated tube; 3-1. Inflation screw; 3-2. Sealing cap; 3-3. Corrugated cylinder; 4. Outer shell; 5. Capacitor core; 5-1a. High voltage lead; 5-1b. Low voltage lead; 5-2. Clamping plate; 5-21. Screw; 5-22. Epoxy casting body; 5-3. Capacitor element; 5-4. Support plate; 5-5. Encapsulation component; 5-6. Partition plate; 5-7. Medium voltage lead; 5-8. Polypropylene film gasket; 6. Lead-out sleeve; 6-1. Medium voltage conductive rod; 6-2. Low voltage conductive rod; 6-3. Epoxy casting body; 7. Bottom cover. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0026] In this utility model, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this utility model, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this utility model.

[0027] In this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number; "above," "below," "within," etc. are understood to include the stated number. In the description of this utility model, if "first" or "second" is used, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0028] In this utility model, unless otherwise explicitly defined, terms such as "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model based on the specific content of the technical solution.

[0029] Reference Figure 1 , Figure 2 As shown, a capacitor voltage divider of this utility model includes: 4. Outer shell; The capacitor core 5 is installed inside the outer casing 4; The upper cover 1 is installed on the upper end of the outer shell 4, and the high voltage terminal of the capacitor core 5 is connected to the upper cover 1; Corrugated pipe 3 is installed on the upper cover 1. The lower cover 7 is installed at the lower end of the outer casing 4; The lead-out sleeve 6 is installed on the lower cover 7. The medium-voltage end and low-voltage end of the capacitor core 5 are led out through the lead-out sleeve 6 to achieve connection with the electromagnetic unit (an external electromagnetic measurement and conversion device used for signal acquisition, processing and output).

[0030] In one embodiment, sealing gaskets 2 are respectively provided between the upper cover 1 and the upper end of the outer shell 4, and between the lower cover 7 and the lower end of the outer shell 4. The upper cover 1, lower cover 7, outer shell 4, lead-out sleeve 6, and sealing gaskets 2 together constitute a fully sealed capacitor voltage divider, achieving a fully sealed and maintenance-free capacitor and reducing waste emissions.

[0031] In one embodiment, refer to Figure 3 As shown, the corrugated pipe 3 includes a corrugated cylinder 3-3 and an inflation screw 3-1 and a sealing cap 3-2 respectively disposed at both ends of the axial direction of the corrugated cylinder 3-3. Gas is filled into the corrugated cylinder 3-3 through the inflation screw 3-1.

[0032] The air-filled screw 3-1, sealing cap 3-2, and bellows 3-3 are welded using plasma welding, ensuring a mechanical lifespan exceeding 10,000 cycles of limit expansion and contraction without elastic deformation throughout the entire temperature compensation range. The bellows 3 is pressurized with gas through the valve core of the air-filled screw 3-1, maintaining positive pressure within the capacitive voltage divider throughout the entire temperature compensation range. Compared to the industry-standard external expander, eliminating the metal ring cover saves costs and improves vibration resistance.

[0033] In one embodiment, refer to Figure 4 As shown, the lead-out sleeve 6 includes an epoxy casting body 6-3 and a medium-voltage conductive rod 6-1 and a low-voltage conductive rod 6-2 disposed on the epoxy casting body 6-3; The low-voltage conductive rod 6-2 is welded to the shielding mesh to improve the distribution of the electrode electric field and increase the level of partial discharge. The two ends of the medium-voltage conductive rod 6-1 are provided with first threaded holes. The first threaded holes are used for the medium-voltage end of the capacitor core 5 to be led out to achieve a reliable connection with the inside of the electromagnetic unit. The low-voltage conductive rod 6-2 has a second threaded hole on its side, which is used to lead out the N terminal of the end screen of the capacitor core 5.

[0034] The medium and low pressure leads use an integrated bushing instead of a separate bushing, which is suitable for the assembly requirements of small inner diameter bushings, can reduce the size of the voltage divider and reduce product costs.

[0035] In one embodiment, refer to Figure 5 , Figure 6 As shown, the capacitor core 5 includes several capacitor elements 5-3 connected in series, clamping plates 5-2 located at the upper and lower ends of the capacitor elements 5-3, and support plates 5-4 located at the side ends. (Refer to...) Figure 8 As shown, calculate the number of component strings required for C1 and C2 based on the rated voltage and voltage division ratio.

[0036] Several capacitor elements 5-3 are packaged in groups, with each group separated by a sealing element 5-5 and a partition 5-6. This minimizes the deformation of the capacitor core 5, reducing honeycomb or S-shaped deformation of the elements and improving the partial discharge and insulation withstand level of the capacitor divider.

[0037] In one embodiment, the dielectric between electrodes 5 and 3 of the capacitor element consists of two layers of polypropylene film and one layer of capacitor paper BI, while the insulating oil is phenylethyl phenylethane. Capacitor paper BI is a polar dielectric, while the polypropylene film and phenylethyl phenylethane oil are weakly polar dielectrics. The paper-to-film thickness ratio is 1:3, significantly reducing dielectric active power loss at the source. The dielectric constant of the polypropylene film decreases with increasing temperature, while the dielectric constant of capacitor paper BI increases with increasing temperature. This complementary property of dielectric constant variation with temperature ensures that the temperature coefficient of capacitance does not exceed 2 × 10⁻⁶. -4 This improves the temperature stability of the partial pressure ratio.

[0038] In one embodiment, the capacitor core 5 further includes a high-voltage lead 5-1a, a medium-voltage lead 5-7, and a low-voltage lead 5-1b; the high-voltage lead 5-1a is equipotentially connected to the upper cover 1, the low-voltage lead 5-1b is connected to the low-voltage conductive rod 6-2, and the medium-voltage lead 5-7 is connected to the medium-voltage conductive rod 6-1.

[0039] In one embodiment, the high-voltage lead 5-1a, the medium-voltage lead 5-7, and the low-voltage lead 5-1b all comprise welded polytetrafluoroethylene (PTFE) wires and tin-plated copper foil. The tin-plated copper foil is crimped into contact with the capacitor element 5-3, and a crimp terminal is welded to one end of the PTFE wire. PTFE wires replace commonly used tin-plated copper stranded wires or tin-plated copper foil for the high-voltage, low-voltage, and medium-voltage leads. PTFE has a high dielectric constant, which effectively improves the electric field on the conductor surface and enhances partial discharge performance.

[0040] In one embodiment, refer to Figure 7 As shown, the clamping plates 5-2 at the upper and lower ends of the capacitor core 5 include an epoxy casting molded body 5-22 and several copper screws 5-21 embedded in the epoxy casting molded body 5-22 and connected by metal, which avoids partial discharge caused by floating potential. The structure of the clamping plate 5-2 integrally cast has the advantages of small size, low cost and energy saving.

[0041] In one embodiment, a polypropylene film gasket 5-8 is provided between the low-voltage end and the grounding end of the capacitor core 5. The number and height of the polypropylene film gaskets 5-8 are designed according to the voltage level and the insulation requirements of the low-voltage end to ground, ensuring that the stray capacitance and stray conductance of the low-voltage end to ground are better than the national standard requirements.

[0042] By rationally selecting the main components and optimizing the structural layout of the capacitive voltage divider, advantages such as small size, light weight, and high specific characteristics are achieved. This capacitive voltage divider features low dielectric loss, stable and excellent electrical performance, long lifespan, and high resource utilization. Simultaneously, the product adopts a fully sealed structural design, requiring no maintenance and effectively reducing waste, thus possessing higher energy-saving and environmental protection value. This capacitive voltage divider features small size, light weight, high specific characteristics, excellent electrical performance, fully sealed maintenance-free operation, and energy saving and environmental protection.

[0043] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although this utility model has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A capacitor voltage divider, characterized in that, include: Outer shell (4); The capacitor core (5) is installed inside the outer casing (4); The top cover (1) is installed on the upper end of the outer shell (4), and the high voltage end of the capacitor core (5) is connected to the top cover (1); A corrugated pipe (3) is installed on the upper cover (1). The lower cover (7) is installed at the lower end of the outer shell (4); The lead-out sleeve (6) is installed on the lower cover (7). The medium-voltage end and low-voltage end of the capacitor core (5) are led out through the lead-out sleeve (6) to achieve connection with the electromagnetic unit.

2. A capacitor voltage divider according to claim 1, characterized in that, A sealing gasket (2) is provided between the upper cover (1) and the upper end of the outer shell (4), and between the lower cover (7) and the lower end of the outer shell (4).

3. A capacitor voltage divider according to claim 1, characterized in that, The corrugated pipe (3) includes a corrugated cylinder (3-3) and an inflation screw (3-1) and a sealing cap (3-2) respectively disposed at both ends of the axial direction of the corrugated cylinder (3-3). Gas is filled into the corrugated cylinder (3-3) through the inflation screw (3-1).

4. A capacitor voltage divider according to claim 1, characterized in that, The lead-out sleeve (6) includes an epoxy casting body (6-3) and a medium-voltage conductive rod (6-1) and a low-voltage conductive rod (6-2) disposed on the epoxy casting body (6-3). The low-voltage conductive rod (6-2) is welded to the shielding mesh. The two ends of the medium-voltage conductive rod (6-1) are provided with first threaded holes. The first threaded holes are used for the medium-voltage end of the capacitor core (5) to be led out and connected to the inside of the electromagnetic unit. The low-voltage conductive rod (6-2) has a second threaded hole on its side, which is used to lead out the N terminal of the end screen of the capacitor core (5).

5. A capacitor voltage divider according to claim 4, characterized in that, The capacitor core (5) includes several capacitor elements (5-3) connected in series, clamping plates (5-2) located at the upper and lower ends of the capacitor elements (5-3), and support plates (5-4) located at the side ends. The capacitor elements (5-3) are packaged in groups, and each group is isolated from the others by a sealing component (5-5) and a partition (5-6).

6. A capacitor voltage divider according to claim 5, characterized in that, The capacitor core (5) also includes a high voltage lead (5-1a), a medium voltage lead (5-7), and a low voltage lead (5-1b); the high voltage lead (5-1a) is equipotentially connected to the upper cover (1), the low voltage lead (5-1b) is connected to the low voltage conductive rod (6-2), and the medium voltage lead (5-7) is connected to the medium voltage conductive rod (6-1).

7. A capacitor voltage divider according to claim 6, characterized in that, The high-voltage lead (5-1a), the medium-voltage lead (5-7), and the low-voltage lead (5-1b) all include a welded polytetrafluoroethylene wire and a tin-plated copper foil. The tin-plated copper foil is in crimped contact with the capacitor element (5-3), and a crimp terminal is welded to one end of the polytetrafluoroethylene wire.

8. A capacitor voltage divider according to claim 5, characterized in that, The clamping plates (5-2) at the upper and lower ends of the capacitor core (5) include an epoxy casting molded body (5-22) and a number of copper screws (5-21) embedded in the epoxy casting molded body (5-22) and connected by metal.

9. A capacitor voltage divider according to claim 1, characterized in that, A polypropylene film gasket (5-8) is provided between the low-voltage end and the ground end of the capacitor core (5).

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