A noise reduction device and method for a power filter capacitor

Abstract

The present invention discloses a noise reduction device and a noise reduction method for a power filter capacitor, characterized in that: it includes a sound insulation cover structure and a sound absorption cavity structure. The sound insulation cover structure is fixedly arranged on the top of the capacitor body, and an air cavity is formed between the interior of the sound insulation cover structure and the top wall of the capacitor body for reflecting and absorbing the energy of sound waves. The sound absorption cavity structure is hermetically arranged at the bottom of the capacitor body. The present invention can greatly reduce the noise sources with strong directivity at the top and bottom of the capacitor body, thereby greatly reducing the operating noise of the capacitor.

Description

Technical Field

[0001] The present invention relates to a noise reduction device for power capacitors, and particularly to a noise reduction device and a noise reduction method for power filter capacitors. Background Art

[0002] In recent decades, with the progress of power transmission technology, economic development, and increasing energy demand, the construction of UHV DC has entered a period of rapid development. Due to reasons such as large harmonic currents passing through equipment, low noise frequencies emitted by electrical equipment, and large sizes of electrical equipment, the noise generated by converter station equipment is large, has a long propagation distance, and it is not easy to perform noise reduction treatment on the entire converter station. Therefore, it may have a certain impact on the lives of residents near the converter station. Also, due to the continuous deepening of urbanization in China, the population density near converter stations shows an upward trend, so the noise problem of converter stations for UHV DC transmission has attracted increasing attention.

[0003] The noise generation mechanism of the converter station is as follows: When an AC voltage is applied to the capacitor, an electrodynamic force is generated between the plates, causing the plates to vibrate (as shown in Figure 1 a); the vibration of the capacitor plates drives the vibration of the components (as shown in Figure 1 b); the components vibrate under the action of the electric field and are transmitted to the inner wall of the capacitor case, forming case vibration; then the vibration is transmitted to the outside through the case (as shown in Figure 1 c); the relationship between the electrodynamic force generated between the plates and the voltage (as shown in Figure 1 d) shows that the frequency of the noise is twice the voltage frequency. According to the principle of vibration and sound generation of capacitors, using the vibration damping method to suppress the generation of vibration from the source can effectively reduce the generation of capacitor noise; however, since the electrochemical system of the capacitor unit itself is very stable, it is not suitable to make too many changes inside the capacitor unit, and through a large number of experiments, it is known that the capacitor noise has very strong directivity at the top and bottom. Summary of the Invention

[0004] In view of the above problems, the object of the present invention is to provide a noise reduction device and a noise reduction method for power filter capacitors.

[0005] To achieve the above object, the present invention adopts the following technical solutions. A noise reduction device for power filter capacitors, characterized in that: it includes a sound insulation cover structure and a sound absorption cavity structure. The sound insulation cover structure is fixedly arranged on the top of the capacitor body, and an air cavity is formed between the inside of the sound insulation cover structure and the top wall of the capacitor body for reflecting and absorbing the energy of sound waves; the sound absorption cavity structure is hermetically arranged at the bottom of the capacitor body.

[0006] Preferably, the sound insulation cover structure includes a cover shell provided on the top of the capacitor body, a first sound absorption layer body filled in the cover shell and fixed on the inner top wall of the cover shell, and an air cavity is formed between the first sound absorption layer body and the top wall of the capacitor body in the cover shell.

[0007] Preferably, the first sound absorption layer body includes a surface layer, a first absorption layer, a blocking layer, a second absorption layer, and an installation layer that are tightly bonded in sequence from top to bottom; the surface layer is made of a flame-retardant and waterproof fiber cloth, both the first absorption layer and the second absorption layer are made of flame-retardant and waterproof porous sound-absorbing cotton, the blocking layer is made of a flame-retardant polyethylene rubber plate, and the installation layer is a sticky glue layer; the installation layer of the first sound absorption layer body faces upward and is pasted on the inner top wall of the cover shell.

[0008] Preferably, the surface layer, the first absorption layer, the blocking layer, the second absorption layer, and the installation layer are sequentially bonded with a flame-retardant strong glue to form the first sound absorption layer body.

[0009] Preferably, the thickness of the first sound absorption layer body is between 35 and 50 mm, and the height of the air cavity is 15 to 20 mm;

[0010] The bottom of the cover shell is open, and a through hole for the outgoing wire sleeve on the capacitor body to pass through is provided at the top. The cover shell covers the top of the capacitor body and is fixedly connected to the capacitor body by bolts.

[0011] Preferably, the sound absorption cavity structure includes a shell hermetically connected to the bottom of the capacitor body, a partition is fixedly provided between the top of the shell and the bottom of the capacitor body, and a second sound absorption layer body is filled in the shell.

[0012] Preferably, the second sound absorption layer body is made of a porous sound-absorbing material, and the porosity of the porous sound-absorbing material is between 3 and 10%.

[0013] Preferably, the top of the shell is open, double cross-shaped reinforcing ribs are provided in the shell, the second sound absorption layer body is filled in the space surrounded by the double cross-shaped reinforcing ribs and the inner wall of the shell, the shell is fixedly connected to the bottom of the capacitor body, and the double cross-shaped reinforcing ribs are welded and fixed on the partition.

[0014] Preferably, the height of the shell is between 30 mm and 60 mm, and the double cross-shaped reinforcing ribs are made of square steel with a thickness of 5 mm * 5 mm; the double cross-shaped reinforcing ribs are centrosymmetric structures, and the distance between the two cross bars on the double cross-shaped reinforcing ribs is 100 mm.

[0015] The present invention also provides a method for reducing the noise of a power filter capacitor, which is characterized by including the following steps:

[0016] According to the requirements of the capacitance of the capacitor, the insulation level to the shell, and the oil injection process, by adjusting the thickness or quantity of the insulating plates in the capacitor core to increase the internal compression coefficient of the capacitor unit, the core in the capacitor body is fixed in the case of the capacitor body through insulating parts;

[0017] A sound insulation cover structure is installed at the top of the capacitor body, and a sound absorption cavity structure is installed at the bottom of the capacitor body.

[0018] The present invention adopts the above technical solutions, and has the following advantages: by respectively arranging a sound insulation cover structure and a sound absorption cavity structure at the top and bottom of the capacitor body, the present invention can greatly reduce the noise sources with strong directivity at the top and bottom of the capacitor body, thereby greatly reducing the operating noise of the capacitor. Description of the Drawings

[0019] Figure 1 is a schematic diagram of the noise generation mechanism of the power capacitor; Figure 1 a is a schematic diagram of the vibration principle of the capacitor plate; Figure 1 b is a schematic diagram of the vibration principle of the component; Figure 1 c is a schematic diagram of the vibration principle of the capacitor case; Figure 1 d is a diagram of the relationship between the electrodynamic force generated between the plates and the voltage;

[0020] Figure 2 is a front view structure schematic diagram of the present invention;

[0021] Figure 3 is a side view structure schematic diagram of the present invention;

[0022] Figure 4 is a front view of the sound insulation cover structure of the present invention;

[0023] Figure 5 is a side view of the sound insulation cover structure of the present invention;

[0024] Figure 6 is a top view of the sound insulation cover structure of the present invention;

[0025] Figure 7 is a schematic diagram of the first sound absorption layer body of the present invention;

[0026] Figure 8 is a schematic diagram of the sound absorption cavity structure of the present invention;

[0027] Figure 9 is a top view of the sound absorption cavity structure of the present invention; Detailed Embodiments

[0028] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, so as to more clearly understand the purpose, features, and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not limitations on the scope of the present invention, but only to illustrate the essential spirit of the technical solution of the present invention.

[0029] As Figure 2 , Figure 3 shown, the present invention provides a noise reduction device for a power filter capacitor, which includes a sound insulation cover structure 1 and a sound absorption cavity structure 2. The sound insulation cover structure 1 is fixedly arranged on the top of the capacitor body 3, and an air cavity 4 is formed between the inside of the sound insulation cover structure 1 and the top wall of the capacitor body 3 for reflecting and absorbing the energy of sound waves; the sound absorption cavity structure 2 is hermetically arranged at the bottom of the capacitor body 3.

[0030] In the above embodiment, preferably, as Figures 4 - 6 shown, the sound insulation cover structure 1 includes a cover shell 11 arranged on the top of the capacitor body 3, a first sound absorption layer body 12 filled in the cover shell 11 and fixed on its inner top wall, and an air cavity 4 is formed in the cover shell 11 and between the first sound absorption layer body 12 and the top wall of the capacitor body 3.

[0031] In the above embodiment, preferably, as Figure 7 shown, the first sound absorption layer body 12 includes a surface layer 121, a first absorption layer 122, a blocking layer 123, a second absorption layer 124, and an installation layer 125 that are tightly bonded in sequence from top to bottom; the surface layer 121 is made of a fiber cloth with flame retardant and waterproof properties, both the first absorption layer 122 and the second absorption layer 124 are made of porous sound absorption cotton with flame retardant and waterproof properties, the blocking layer 123 is made of a polyethylene rubber plate with flame retardant properties, the installation layer 125 is a viscous glue layer, and the installation layer 125 of the first sound absorption layer body 12 faces upward and is pasted on the inner top wall of the cover shell 11, so that the first sound absorption layer body 12 is fixed on the inner top wall of the cover shell 11. When in use, when the noise coming from the top of the capacitor body 3 passes through the first sound absorption layer body 12, the surface layer 121 of the first sound absorption layer body 12 reflects the high-frequency sound waves of the noise, the first absorption layer 122 and the second absorption layer 124 absorb the noise in the full frequency range, and the blocking layer 123 continuously reflects the sound waves to the first absorption layer 122 and the second absorption layer 124, so that the noise sound waves are absorbed and consumed multiple times in the first absorption layer 122 and the second absorption layer 124, and finally most of the noise at the top of the capacitor body 3 is absorbed by the first sound absorption layer body 12, greatly reducing the noise at the top of the capacitor body 3. At the same time, because the sound absorption material has the characteristics of water repellency and flame retardancy, it can ensure that the insulator lead-out part of the capacitor body 3 has sufficient electrical insulation.

[0032] In the above embodiments, preferably, the surface layer 121, the first absorption layer 122, the blocking layer 123, the second absorption layer 124, and the mounting layer 125 are sequentially bonded with a flame-retardant strong glue to form the first sound absorption layer body 12.

[0033] In the above embodiments, preferably, the thickness of the first sound absorption layer body 12 is between 35 and 50 mm, and the height of the air cavity 4 is 15 to 20 mm.

[0034] In the above embodiments, preferably, the bottom of the housing 11 is open, and a through hole 13 is provided at the top for the lead-out sleeve on the capacitor body 3 to pass through. The housing 11 covers the top of the capacitor body 3 and is fixedly connected to the capacitor body 3 by bolts.

[0035] In the above embodiments, preferably, as Figure 1 , Figure 8 , Figure 9 shown, the sound absorption cavity structure 2 includes a housing 21 sealed and connected to the bottom of the capacitor body 3. A partition 5 is fixedly provided between the top of the housing 21 and the bottom of the capacitor body 3, and a second sound absorption layer body 22 is filled in the housing 21.

[0036] In the above embodiments, the second sound absorption layer body 22 is made of a porous sound absorption material, and the porosity of the porous sound absorption material is between 3 and 10% to achieve the best energy absorption and noise reduction effect.

[0037] In the above embodiments, preferably, the top of the housing 21 is open, and a double cross-shaped reinforcing rib 23 is provided inside the housing 21. The second sound absorption layer body 22 is filled in the space surrounded by the double cross-shaped reinforcing rib 23 and the inner wall of the housing 21. The housing 21 is fixedly connected (such as by argon arc welding) to the bottom of the capacitor body 3, and the double cross-shaped reinforcing rib 23 is welded and fixed to the partition 5 to improve the stiffness of the housing 21 and make the resonance frequency of the housing 21 far from the noise sound wave frequency.

[0038] In the above embodiments, preferably, the height of the housing 21 is between 30 mm and 60 mm, and the double cross-shaped reinforcing rib 23 is made of a square steel with a thickness of 5 mm * 5 mm; the distance between the two cross bars on the double cross-shaped reinforcing rib 23 is 100 mm, and the double cross-shaped reinforcing rib 23 has a central symmetry structure.

[0039] Based on the above-provided noise reduction device for a power filtering capacitor, the present invention also provides a noise reduction method for a power filtering capacitor, which includes the following steps:

[0040] S1. Adjust the internal structure of the capacitor body 3, increase the internal pressing coefficient of the capacitor unit, and fix the core in the capacitor body 3 in the case of the capacitor body 3 through insulating parts (such as films or electrical insulating cardboard, etc.).

[0041] Specifically, according to the requirements of the capacitor capacitance, the insulation level to the shell, and the oil injection process, the thickness or quantity of the insulating plates in the capacitor core can be adjusted to increase the compaction coefficient inside the capacitor unit.

[0042] S2. Install the above-mentioned sound insulation cover structure 1 on the top of the capacitor body 3, and install the above-mentioned sound absorption cavity structure 2 on the bottom of the capacitor body 3.

[0043] The noise reduction structure and method of the present invention can greatly reduce the operating noise of the capacitor while ensuring the original electrical insulation performance and heat dissipation performance of the capacitor body 3.

[0044] The present invention is only illustrated by the above embodiments, and the structures, installation positions and connections of each component can be changed. Based on the technical solution of the present invention, any improvement or equivalent transformation made to individual components according to the principle of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A noise reduction device for a power filter capacitor, characterized in that: it includes a sound insulation cover structure (1) and a sound absorption cavity structure (2). The sound insulation cover structure (1) is fixedly arranged on the top of the capacitor body (3), and an air cavity (4) is formed between the inside of the sound insulation cover structure (1) and the top wall of the capacitor body (3) for reflecting and absorbing the energy of sound waves; the sound absorption cavity structure (2) is hermetically arranged at the bottom of the capacitor body (3); the sound insulation cover structure (1) includes a cover shell (11) arranged on the top of the capacitor body (3), a first sound absorption layer body (12) filled in the cover shell (11) and fixed on the inner top wall of the cover shell (11), and the air cavity (4) is formed between the first sound absorption layer body (12) and the top wall of the capacitor body (3) in the cover shell (11); the first sound absorption layer body (12) includes a surface layer (121), a first absorption layer (122), a blocking layer (123), a second absorption layer (124) and an installation layer (125) which are tightly bonded in sequence from top to bottom; the surface layer (121) is made of flame-retardant and waterproof fiber cloth, both the first absorption layer (122) and the second absorption layer (124) are made of flame-retardant and waterproof porous sound absorption cotton, the blocking layer (123) is made of flame-retardant polyethylene rubber plate, and the installation layer (125) is an adhesive layer; the installation layer (125) of the first sound absorption layer body (12) faces upward and is pasted on the inner top wall of the cover shell (11).

2. The noise reduction device for a power filter capacitor according to claim 1, characterized in that: the surface layer (121), the first absorption layer (122), the blocking layer (123), the second absorption layer (124) and the installation layer (125) are sequentially bonded by a flame-retardant strong glue to form the first sound absorption layer body (12).

3. The noise reduction device for a power filter capacitor according to claim 1, characterized in that: the thickness of the first sound absorption layer body (12) is between 35 and 50 mm, and the height of the air cavity (4) is 15 to 20 mm; the bottom of the cover shell (11) is open, and a through hole (13) for the outgoing line sleeve on the capacitor body (3) to pass through is opened at the top. The cover shell (11) covers the top of the capacitor body (3) and is fixedly connected to the capacitor body (3) by bolts.

4. The noise reduction device for a power filter capacitor according to claim 1, characterized in that: the sound absorption cavity structure (2) includes a shell (21) hermetically connected to the bottom of the capacitor body (3), a partition (5) is fixedly arranged between the top of the shell (21) and the bottom of the capacitor body (3), and a second sound absorption layer body (22) is filled in the shell (21).

5. The noise reduction device for a power filter capacitor according to claim 4, characterized in that: the second sound absorption layer body (22) is made of a porous sound absorption material, and the porosity of the porous sound absorption material is between 3 and 10%.

6. The noise reduction device for a power filter capacitor according to claim 4, It is characterized in that: The top of the housing (21) is open. A double-cross reinforcing rib (23) is arranged inside the housing (21). The second sound-absorbing layer body (22) is filled in the space surrounded by the double-cross reinforcing rib (23) and the inner wall of the housing (21). The housing (21) is fixedly connected to the bottom of the capacitor body (3). The double-cross reinforcing rib (23) is fixedly welded to the partition plate (5).

7. A noise reduction device for a power filter capacitor according to claim 6, It is characterized in that: The height of the housing (21) is between 30 mm and 60 mm. The double-cross reinforcing rib (23) is made of square steel with a thickness of 5 mm * 5 mm. The double-cross reinforcing rib (23) has a centrosymmetric structure, and the distance between the two cross bars on the double-cross reinforcing rib (23) is 100 mm.

8. A method for reducing noise of a power filter capacitor based on the noise reduction device according to any one of claims 1 to 7, It is characterized in that, including the following steps: According to the requirements of the capacitor capacitance, the insulation level to the shell and the oil injection process, by adjusting the thickness or quantity of the insulating plates in the capacitor core to increase the internal pressing coefficient of the capacitor unit, the core in the capacitor body (3) is fixed in the case of the capacitor body (3) through insulating parts; Install a sound insulation cover structure (1) on the top of the capacitor body (3), and install a sound absorption cavity structure (2) on the bottom of the capacitor body (3).

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