Oiled paper capacitive bushing with core sinking prevention structure

Abstract

The utility model belongs to the field of high-voltage electrical equipment, and particularly relates to an oiled paper capacitor type bushing with a core sinking prevention structure, which comprises a central conductor, an oiled paper capacitor core body arranged outside the central conductor, and a lower porcelain bushing and a voltage-sharing ball arranged at the lower end of the oiled paper capacitor core body. At least one core body step is arranged at the conical part of the lower end of the oiled paper capacitor core body, an insulating supporting sheath is arranged between the oiled paper capacitor core body and the inner cavity of the lower porcelain bushing, an inner cavity step matched with the core body step is arranged on the inner cavity wall of the insulating supporting sheath, and the insulating supporting sheath supports the oiled paper capacitor core body through the inner cavity step and the core body step. The device has the advantages of being reasonable in structure, stable and reliable in work and safe to use.

Description

Technical Field

[0001] This utility model belongs to the field of high-voltage electrical equipment, specifically relating to an oil-paper capacitor bushing with an anti-core sinking structure. Background Technology

[0002] In high-voltage power transformers, oil-paper capacitor bushings are a key insulation component. Their core structure consists of two parts: internal insulation and external insulation. The internal insulation is a cylindrical capacitor core, formed by layers of insulating paper and multiple metal plates rolled onto the central conductor, creating a unique gradient structure that effectively controls the axial and radial electric field distribution, achieving uniform electric field strength at the ends. The external insulation typically uses high-strength porcelain bushings, providing not only mechanical protection but also crucial electrical insulation.

[0003] Therefore, the stability and reliability of the capacitor core, which provides internal insulation, in the oil-paper capacitor bushing is a key factor in ensuring the normal operation of the transformer.

[0004] However, in actual production, existing oil-paper capacitor bushings may experience a series of bushing failures due to design and process defects. The most critical of these is the sinking and displacement of the capacitor core inside the bushing.

[0005] To facilitate bushing assembly, a relatively large gap is typically maintained between the inner cavity of the ceramic sleeve at the oil end of the bushing and the capacitor core. If the adhesive strength between the innermost layer of cable paper and the central guide tube is insufficient, or if the tension during capacitor core winding is too low, the overall friction of the capacitor core on the central guide tube can easily become insufficient. During bushing operation, the capacitor core's own weight and high-frequency vibrations will accelerate its downward displacement along the central guide tube within the bushing.

[0006] The sinking and displacement of the capacitor core will disrupt the original electric field distribution, which will not only increase the probability of discharge and accelerate the aging process of the insulation material, but also lead to the breakdown of the insulation layer. Moreover, the sinking of the capacitor core may affect the normal operation of the end screen grounding electrode, causing the phenomenon of loose connection, arc discharge, and even bushing explosion, which will seriously affect the reliability of power grid operation. Utility Model Content

[0007] The purpose of this utility model is to provide an oil-paper capacitor bushing with an anti-core sinking structure. An insulating support sleeve is added to the tapered part of the oil end of the oil-paper capacitor core to provide additional support for the core, effectively preventing the core from sinking and ensuring the safe operation of the bushing.

[0008] This utility model is achieved through the following technical solution:

[0009] A paper capacitor bushing with an anti-core sinking structure includes a central conductor, an oil paper capacitor core outside the central conductor, and a lower ceramic sleeve at the lower end of the oil paper capacitor core. The key feature is that the tapered portion at the lower end of the oil paper capacitor core has at least one core step, and an insulating support sleeve is provided between the oil paper capacitor core and the inner cavity of the lower ceramic sleeve. The inner wall of the insulating support sleeve has an inner cavity step that matches the core step, and the insulating support sleeve supports the oil paper capacitor core through the inner cavity step and the core step.

[0010] Furthermore, the insulating support sleeve of this utility model is conical, and the inner cavity taper is parallel to the taper of the oil-paper capacitor core and leaves an oil gap.

[0011] The oil gap is preferably 3-5mm.

[0012] Furthermore, the surface of the insulating support sleeve of this utility model is provided with multiple narrow strip-shaped oil injection channels evenly arranged along the axis.

[0013] Furthermore, the insulating support sleeve of this utility model is an integral structure.

[0014] The insulating support sleeve of this utility model is preferably formed by integral processing or injection molding.

[0015] Furthermore, the insulating support sleeve of this utility model is made of oil-resistant nylon or polytetrafluoroethylene.

[0016] This utility model has the following advantages and positive effects:

[0017] 1) The oil-paper capacitor bushing of this utility model adds an insulating support sleeve to the tapered part of the oil end of the oil-paper capacitor core. The inner cavity step of the support sleeve is precisely matched with the core step, and the bottom is tightly connected with the sealing element in the equalizing ball. It can provide additional support force to the oil-paper capacitor core, and can withstand the weight of the oil-paper capacitor core itself and various stresses during operation. It can fundamentally and effectively prevent the core from sinking, so as to ensure the safe operation of the bushing.

[0018] 2) The oil-paper capacitor bushing of this utility model has multiple narrow strip-shaped oil injection channels evenly arranged along the axis on the surface of the insulating support sheath. This not only helps to dissipate heat and reduce the possibility of air bubble accumulation, but also allows the transformer oil to flow freely in the bushing. This can effectively penetrate the inside of the oil-paper capacitor core and the oil gap between the oil-paper capacitor core and the insulating support sheath, thereby improving the overall insulation performance and long-term operational reliability of the bushing. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model;

[0020] Figure 2 for Figure 1Enlarged schematic diagram of part I in the diagram;

[0021] Figure 3 This is a schematic diagram of the structure of the insulating support sleeve of this utility model;

[0022] Figure 4 for Figure 3 A schematic diagram of the AA cross-sectional structure in the diagram;

[0023] Figure 5 for Figure 3 A top-view structural diagram.

[0024] As shown in the figure: 1. Terminal block; 2. Oil conservator assembly; 3. Upper porcelain bushing; 4. Metal flange; 5. Center conductor; 6. Oil-paper capacitor core; 7. Insulating support sleeve; 8. Transformer oil; 9. Lower porcelain bushing; 10. Lower seal; 11. Equalizing ball; 12. Core step; 13. Oil injection channel; 14. Inner cavity step. Detailed Implementation

[0025] The embodiments of the present utility model will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present utility model and are not intended to limit its scope of protection. It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which this utility model pertains.

[0026] like Figure 1 , Figure 2 As shown: A paper capacitor core 6 is provided outside the center conductor 5. From top to bottom, the upper outer sides of the center conductor 5 and the paper capacitor core 6 are provided with a terminal 1, an oil conservator assembly 2, an upper porcelain sleeve 3, and a metal flange 4. From top to bottom, the lower outer sides of the center conductor 5 and the paper capacitor core 6 are provided with a lower porcelain sleeve 9, a lower seal 10, and an equalizing ball 11. The tapered part of the oil end of the paper capacitor core 6 has an annular core step 12. An insulating support sleeve 7 is provided between the inner cavity of the paper capacitor core 6 and the lower porcelain sleeve 9. The inner cavity wall of the insulating support sleeve 7 is provided with an inner cavity step 14 that matches the core step 12. The lower end of the insulating support sleeve 7 is tightly fitted with the lower seal 11 in the equalizing ball 11 (i.e., the lower end of the insulating support sleeve 7 presses against the lower seal 11). The insulating support sleeve 7 supports the paper capacitor core 6 through the inner cavity step 14 and the core step 12.

[0027] like Figure 3 , Figure 4 , Figure 5 As shown: The surface of the insulating support sleeve 7 is provided with multiple narrow strip-shaped oil injection channels 13 evenly arranged along the axis.

[0028] The following describes the manufacturing process of this utility model in detail, taking the fabrication of a 252kV oil-paper capacitor transformer bushing as an example:

[0029] First, prepare a dried 252kV oil-paper capacitor core 6. Pass the metal flange 4 through the oil end of the oil-paper capacitor core 6 and install it in the lower middle part of the oil-paper capacitor core 6. Then, install the insulating support sleeve 7 at the oil end of the oil-paper capacitor core 6, so that the insulating support sleeve 7 passes through the end of the center conductor 5 and is installed in the tapered part of the oil end of the oil-paper capacitor core 6. Next, install the lower porcelain bushing 9 and tighten the lower seal 10 so that the insulating support sleeve 7 is in close contact with the step 12 of the oil end of the oil-paper capacitor core 6. Install the porcelain bushing 3 and the oil conservator assembly 2 in sequence at the air end. Finally, install the terminal block 1 and the equalizing ball 11 to complete the overall assembly of the bushing. Finally, the bushing is vacuumed and injected with qualified transformer oil 8. A complete 252kV oil-paper capacitor transformer bushing is now manufactured.

[0030] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A paper-based capacitor bushing with an anti-core sinking structure, comprising a central conductor, an oil-paper capacitor core disposed outside the central conductor, and a lower ceramic sleeve and a voltage equalizing ball disposed at the lower end of the oil-paper capacitor core, characterized in that... The tapered portion at the lower end of the oil-paper capacitor core is provided with at least one core step. An insulating support sleeve is provided between the oil-paper capacitor core and the inner cavity of the lower ceramic sleeve. The inner wall of the insulating support sleeve is provided with an inner cavity step that matches the core step. The insulating support sleeve supports the oil-paper capacitor core through the inner cavity step and the core step.

2. The oil-paper capacitor bushing with an anti-core sinking structure according to claim 1, characterized in that... The insulating support sheath is tapered, and the inner cone is parallel to the cone of the oil-paper capacitor core, with an oil gap.

3. The oil-paper capacitor bushing with an anti-core sinking structure according to claim 1, characterized in that... The surface of the insulating support sheath is provided with multiple narrow strip-shaped oil injection channels evenly arranged along the axis.

4. The oil-paper capacitor bushing with an anti-core sinking structure according to claim 1, characterized in that... The insulating support sheath is an integral structure.

5. An oil-paper capacitor bushing with an anti-core sinking structure according to claim 1, 2, 3, or 4, characterized in that... The insulating support sleeve is made of oil-resistant nylon or polytetrafluoroethylene.

Images