KR100879887B1 - Acoustic absorption and resonance type acoustic baffle and installation method for noise attenuation of transformer - Google Patents

Abstract

An acoustic absorption and resonance type acoustic baffle and an installing method thereof are provided to reduce a noise outputted from a transformer through an air duct. A plurality of vertical baffles(10) are built to be approximately vertical to a surface with a predetermined interval. A plurality of transverse baffles(20) are transversely installed between the vertical baffles and have a width smaller than the interval of the vertical baffles. The interval of the transverse baffles installed in an upper layer and a lower layer is one of the 600 ~ 900 mm or 300 ~ 450 mm.

Description

Acoustic absorption and resonance type acoustic baffle and installation method for noise attenuation of transformer}

The present invention relates to a sound absorbing and resonance acoustic baffle for reducing transformer noise, and a method of installing the same. More specifically, the sound absorbing and suppressing transformer for noise reduction installed in a wind tunnel is a passage through which noise generated in a transformer of an indoor substation is spread outside. Resonance acoustic baffle and its installation method.

Korean Patent Application No. 10-1999-0029093 [Resonant Noise Reduction Device for Transformer Enclosure Structure], which is a prior art, installs a transformer, etc., as a noise source inside, and spreads the noise by blocking the noise inside. It should be surrounded by a sealed box to prevent it, but in the inner wall of the sealed box, the main noise source of the pure sound type generated from the noise source is extinguished from the inner wall to prevent it from being released to the outside in accordance with the pure sound component transmitted by the resonance phenomenon in the sealed space. There is a resonance noise reduction device for a transformer hermetic structure, characterized in that by installing a Helmholtz resonator device at a predetermined interval on the inner wall.

In addition, Korean patent registration of Hanbat University Industry-Academic Cooperation No. 0704555 [Active Noise Attenuator for Active Transformer, Sound Attenuator for Active Transformer with Soundproof Member, and Active Transformer Noise Attenuator with Soundproof Member and Sound Absorber] is active noise control. The transformer noise attenuation device using the noise control device and the sound absorbing device and the sound absorber called the resonator are additionally used to simultaneously use the active and passive noise control means.

However, this conventional technology has a problem in that the sound insulation member having a structure that simply surrounds the noise source has a limit in the amount of noise reduction and may cause a failure in cooling of the transformer when the surrounding space of the transformer is excessively closed. In the case of the resonator, the noise reduction effect is less than the space occupied by the resonator, and in the structure of the transformer chamber or the wind chamber of the transformer chamber rather than the narrow duct structure, there is a limit in reducing the radiation noise of the transformer with low frequency. In addition, in the case of the device using the active noise control, there is a problem that it has not entered the commercialization stage yet, the investment cost is excessive in its application, and the effect that can be obtained against the cost is relatively small and has not yet been verified.

An object of the present invention is to solve the problems of the prior art, and to provide a sound absorbing and resonance acoustic baffle for reducing transformer noise and a method of installing the same, which can greatly attenuate the noise radiated from the transformer through the wind chamber.

In addition, to provide a sound absorbing and resonant acoustic baffle for reducing transformer noise, and an installation method thereof, which is excellent in economic efficiency, workability, and implementation, and shows a stable noise reduction effect compared to the noise reduction effect.

Sound absorption and resonance acoustic baffle for transformer noise reduction according to the present invention for achieving the object of the present invention, in the wind baffle for attenuating transformer noise, is set at a predetermined interval (D) approximately perpendicular to the ground It includes a plurality of vertical baffles 10 and a plurality of horizontal baffles 20 having a width (W1) less than the distance (D) between the vertical baffles 10 and installed horizontally between the vertical baffles 10. Characterized in that the configuration.

In addition, the sound absorbing and resonance acoustic baffle installation method for transformer noise reduction according to the present invention for achieving the object of the present invention, in the wind baffle installation method for attenuating transformer noise, the plurality of longitudinal baffles 10 Installing at a predetermined interval (D) approximately perpendicular to the ground; And a step 130 for horizontally installing the plurality of horizontal baffles 20 having a width W1 smaller than the distance D between the vertical baffles 10 between the vertical baffles 10. The spacing between the horizontal baffles 20 installed in the upper and lower layers may include one selected from 600 to 900 mm or 300 to 450 mm.

According to the present invention, a problem of the prior art is solved, and a sound absorption / resonance acoustic baffle for reducing transformer noise and a method of installing the same, which can greatly attenuate the noise radiated from the transformer through the wind chamber, are provided.

In addition, there is provided a sound absorbing and resonant acoustic baffle for reducing transformer noise, and an installation method thereof, which is excellent in economic efficiency, workability, and implementation, and exhibits a stable noise reduction effect compared to the noise reduction effect.

By applying an embodiment of the sound absorbing and resonance acoustic baffle for transformer noise reduction according to the present invention and its installation method, it was possible to reduce 11 dB at 120 Hz, 18 dB at 240 Hz, and 29 dB at 360 Hz. Depending on the effect, further noise reduction is possible.

According to the present invention, there is provided a sound absorption / resonance acoustic baffle and a method of installing the same, which can greatly attenuate not only the high frequency component of the transformer noise but also the low frequency component.

Hereinafter, a sound absorption / resonance type acoustic baffle for transformer noise reduction and an installation method according to the present invention will be described in detail according to an embodiment shown in the accompanying drawings.

1 is a schematic diagram of an indoor substation. As shown in FIG. 1, a transformer 1 is disposed in an indoor substation, a lower wind 3 is disposed below the bottom 1, and an upper wind 4 is provided on the roof. By the internal fan (not shown) that is operated for cooling of the transformer, the air at room temperature outside enters the lower wind (3) and exits to the upper wind (4).

The noise of the transformer is caused by the transmission power waveform causing the core, coil and transformer body to vibrate. At this time, since the core vibrates at a frequency corresponding to twice the transmission power frequency, the noise is composed of harmonic components of twice the frequency. For example, since domestic uses 60 (Hz) transmission power, the core vibrates at 120Hz, producing noises in which the harmonic components such as 240Hz, 360Hz, 480Hz are mixed and the frequency spectrum of such transformer noise can be seen in FIG. have.

Transformer noise of the indoor substation transformer room (120 Hz, 240 Hz, 360 Hz, ...) is generated in the transformer room as shown in Figure 1 and radiates to the outside through the lower wind (3). In the present invention, a baffle-type sound absorbing material is installed on the ceiling of the lower wind chamber 3 for the purpose of reducing transformer noise radiating to the outside through the lower wind chamber 3.

2 is a perspective view of a state in which a sound absorbing and resonating acoustic baffle is installed for reducing transformer noise according to an embodiment of the present invention, FIG. 3 is a plan view in which the sound absorbing and resonating acoustic baffle of FIG. 2 is installed, and FIG. 4 is of FIG. It is a front view of the state in which the sound absorption and resonance acoustic baffle was installed.

In the present invention, the baffle is installed in the wind to attenuate the transformer noise. The vertical baffle 10 is erected at predetermined intervals D substantially perpendicular to the ground and is plural. As shown, the longitudinal baffles 10 are preferably plurally oriented to face each other perpendicular to the ground or substation bottom 2. The number of vertical baffles 10 to be erected may vary depending on the size of the lower winds 3.

The plurality of horizontal baffles 20 has a width W1 smaller than the distance D between the vertical baffles 10 and is horizontally installed between the vertical baffles 10. That is, the horizontal baffle 20 is set up substantially perpendicular to the plane formed by the horizontal baffle 20 between the vertical baffles 10 facing each other and is installed to be horizontal to the ground.

The width W1 of the horizontal baffle 20 is smaller than the distance D between the vertical baffles 10. That is, the vertical baffle 10 is installed at a wider interval than the width W1 of the horizontal baffle 20, and a gap (space) forming an air passage 15 between the side of the horizontal baffle 20 and the vertical baffle 10. ) Will exist. As shown in the figure, the horizontal baffle 20 is preferably a long rectangular shape in order to obtain installation convenience and an appropriate noise reduction effect, but is not necessarily limited to this shape. In the embodiment of the present invention, the material of the horizontal baffle 20 and the vertical baffle 10 was PET (POLYESTER, polyester).

Resonator 30 may be embedded in the horizontal baffle 20. Preferably the end of the neck (Neck) of the resonator is located on the upper surface of the horizontal baffle 20, the volume (Volume) of the resonator 30 may be embedded in the interior of the horizontal baffle (20). In the embodiment of the present invention, since the thickness t of the horizontal baffle 20 is 150 mm, it is possible to configure a resonator tuned to 120 Hz or 240 Hz as described above. The resonator may be provided only in a part of the region of one horizontal baffle 20, and the number of the resonators may be changed as desired by the designer. The resonator may be provided on the side of the acoustic baffle that is installed laterally in some cases. The operation and design method of the resonator 30 is well known in the present specification for a clear description of the invention will be omitted. If the resonator's tuning frequency is set to 120Hz or 240Hz, the overall noise reduction effect is equivalent to that of the baffle.

Hereinafter, a preferable spacing between the horizontal baffles 20 will be described. The interval between the horizontal baffles 20 installed in the upper and lower layers is excellent in noise attenuation characteristics when it corresponds to one of approximately 1/4 length of the 120 Hz noise wavelength and 1/4 length of the 240 Hz noise wavelength. The upper and lower intervals between the horizontal baffles 20 are 1/4 of the target frequency noise wavelength to be controlled, which is most advantageous in terms of noise reduction, and the noise reduction effect decreases as far from 1/4 of the target noise wavelength. The cause of the optimum noise attenuation in this range may be due to the influence of reactive attenuation caused by the acoustic resonance and the area change by the transverse baffle 20 of the sound wave.

When the interval between the horizontal baffles 20 installed in the upper and lower layers is 600 to 900 mm, an excellent noise attenuation effect was observed for the noise to be attenuated at 120 Hz, and the interval was 300 to 450 mm when the attenuation was at 240 Hz. Showed excellent noise reduction effect.

The horizontal baffle 20 is provided with three horizontal baffles 22, 23, and 24 in the upper and lower layers between the vertical baffles 10 facing each other, and the first horizontal baffle 22 and the second horizontal baffle 23 adjacent thereto are provided. It is more preferable that the spacing between 600 and 900 mm and the spacing between the second transverse baffle 23 and the third transverse baffle 24 located on the opposite side of the first transverse baffle 22 are 300 to 450 mm.

 When installing the horizontal baffle 20 whose main target is 120 Hz and this 240 Hz noise, the vertical length L of the vertical baffle 10 should be at least 1000 mm in length, preferably in the range of 1000 to 2000 mm. do. This is because the spacing between the horizontal baffles 20 should be about 750 mm for 120 Hz noise reduction, and 375 mm is required for this 240 Hz noise. If it exceeds 2000 mm, workability is inferior.

In the present invention, the interval between the horizontal baffles 20 provided in the upper and lower layers is the wavelength lambda of the target target frequency noise × 1/4 0.8 to the wavelength lambda of the target target frequency noise × 1 / 4) x 1.2 is preferably in the range of length. Outside the range, the resonance phenomenon was reduced and the noise reduction performance was reduced, and the test showed that the noise blocking performance was excellent in this range.

11 is a flowchart illustrating a method for installing the sound absorbing and resonance acoustic baffle of the present invention.

As shown, the sound absorbing and resonating acoustic baffle mounting method according to the present invention is a wind baffle installation method for attenuating transformer noise, a plurality of longitudinal baffles (10) a predetermined interval (D) approximately perpendicular to the ground Step (110) to install; And horizontally installing a plurality of horizontal baffles 20 having a width W1 smaller than an interval D between the vertical baffles 10 between the vertical baffles 10. The interval between the horizontal baffles 20 installed in the upper and lower layers includes one selected from 600 to 900 mm or 300 to 450 mm.

In addition, before the step 110 of installing the plurality of vertical baffles 10, the step 105 of installing the frame 5 to support and fix the baffle in the wind and tuned to one of 120Hz or 240Hz frequency It may be configured to further include; the step (108) for installing the resonator 30 in the horizontal baffle (20).

<First Example >

The height L of the vertical baffle 10 was 1200 mm, and the width W1 of the horizontal baffle 20 was 450 mm. The thickness of the horizontal baffle 20 and the vertical baffle 10 was 150 mm, and the width of the air passage 15 was 200 mm. As a whole arrangement, three horizontal baffles 20 were installed between two vertical baffles 10 facing each other as shown in FIG. 4. The spacing between the horizontal baffles 20 was 700 mm and 350 mm. PET was used for the material.

Hereinafter, the operation of the sound absorbing and resonating acoustic baffle for reducing transformer noise according to an embodiment of the present invention will be described.

noise Reduction  factor

5 is a schematic diagram of noise propagating along a sound absorbing baffle. As shown in Fig. 5, the noise transmitted through the baffle sound absorbing material of the transformer noise can be considered to be reduced by the following three types.

First is the noise attenuated by the sound absorbing material and resonator while traveling along the baffle.

Second, the noise is reduced by the area change caused by the horizontal baffle and the end reflection.

Third, there is noise attenuated while passing through the transverse baffle.

Vertical To baffle (10)  Noise caused by Reduction

The noise to be reduced along the baffles arranged in parallel can be represented by the spacing of the baffles, the thickness of the sound absorbing material and the sound absorption rate (or flow resistance) of the material, where the noise reduction by the resonator is calculated separately.

6 is a graph showing noise reduction characteristics by a general sound absorbing vertical baffle ( Noise and Vibration Control , Ch. 12, edited by Leo L. Beranek, McGraw-Hill Book Company. As in the first embodiment, the sound absorbing material considered is PET (POLYESTER, polyester) having a thickness of 150 mm, and references ( Noise and Vibration According to Control , Ch. 12, edited by Leo L. Beranek, McGraw-Hill Book Company, pages 381-384, the noise reductions for the wavelength and spacing of baffles can be estimated as shown in Table 1.

Noise reduction by sound absorbing material Frequency [Hz] 120 240 360 480 Baffle spacing, ℓ _y ( m ) 0.85 Baffle length, L ( m ) 1.2 Sound absorber thickness, t ( m ) 0.15 Open area ratio, (ℓ _y -t) / ℓ _y 0.85 Wavelength ( m ) 2.74 1.37 0.95 0.71 ℓ _y / λ 0.31 0.62 0.89 1.19 Aℓ _y (dB), (see FIG. 6) 1.1 2.8 3.1 3.2 Noise reduction (dB), Aℓ _y × L / ℓ _y 1.6 4.0 4.4 4.5

Where l _y = D.

horizontal To baffle (20)  Noise caused by Reduction

Figure 7 is a detailed baffle for explaining the noise reduction process by the horizontal baffle according to the present invention. The area change by the horizontal baffle is reduced by the length L ₁ after the area is reduced from S ₁ to S ₂ as shown in Fig. 6, and then the area is changed from S ₂ to S ₁ and then L ₂ It progresses by length, and it can be considered that area change is repeated in this way.

There is an effect that the final noise attenuation by the baffle-type sound absorbing material end reflection before entering the lower air chamber. This end reflection generally reduces noise in the low frequency region, and the amount of noise reduction varies depending on the area of the end. When the area of the transformer noise passing by the sound absorption baffle is 1 m ² , the noise reduction due to the end reflection is about 2 dB at 120 Hz and low at other high frequencies.

Transmission loss by resonator 30

     The propagation loss by the resonator 30 depends on the tuning degree of the resonator for the corresponding frequency range, the number of resonators used, and the arrangement type. In this example, the number and arrangement of resonators were selected to reduce 5 dB using a resonator tuned to 120 Hz.

horizontal Baffle (20)  Direct transmission noise

8 is a graph showing the amount of noise reduction when the noise directly passes through the sound absorbing horizontal baffle 20 (Reference: Noise and Vibration Control , Ch. 10, edited by Leo L. Beranek, McGraw-Hill Book Company.

The noise passing through the horizontal baffle 20 may be calculated as a noise reduction amount per unit length by the flow resistivity of the sound absorbing material used in the baffle. Reference ( Noise and Vibration If the flow resistance of the acoustic material used according to the Control, Ch.10, edited by Leo L. Beranek, McGraw-Hill Book Company) is 2 × 10 ⁴ and rayls / m or more, the noise per unit length when the reductions is 120 Hz Since it is 90 dB at 70 dB and 240 Hz, noise passing through 0.15 m in thickness is reduced by more than 10 dB. Therefore, the noise passing through the horizontal baffle 20 is negligible compared to the noise passing through the horizontal baffle 20 left and right.

<First Example  Test result>

Resonator (30), Vertical baffler 10, and horizontal baffler 20 each noise Reduction

The results of the test to determine the effect of the resonator, the vertical baffle and the horizontal baffle on the overall noise reduction are shown in Table 2 below. First, the noise was measured in the state in which the present invention was not applied, and the noise was measured in the state where only the resonator and the vertical baffle were applied (excluding the horizontal baffle), thereby obtaining the noise reduction amount (dB) by the resonator and the vertical baffle. Next, by applying horizontal baffles, noise was measured at the same point (outside the wind) to obtain the noise reduction by dB. As described above, the noise reduction by the resonator is 5 dB at the noise reduction amount of 6.5 dB by the resonator and the longitudinal baffle at 120 Hz.

Noise reduction due to resonators, longitudinal baffles, and transverse baffles. Frequency [Hz] 120 240 360 480 Noise reduction due to resonator and vertical baffle (dB) 6.5 4.0 4.5 4.5 Noise reduction due to horizontal baffle (dB) 5.0 14.5 25.0 17.0 Total Noise Reduction (dB) 11.5 18.5 29.5 21.5

As can be seen from Table 2, it can be seen that the noise reduction effect by the installation of the horizontal baffle 20 is much larger than the noise reduction effect by the vertical baffle.

Transformer application noise test result

FIG. 9 is an indoor substation transformer noise measured at a certain point outside the wind velocity before the sound absorbing and resonance acoustic baffle of the present invention is installed, and FIG. 10 is a measuring point of FIG. 9 after the sound absorbing and resonance acoustic baffle of the present invention is installed. The noise of an indoor substation transformer measured at the same point. The noise reduction effect as shown in Table 3 below was confirmed.

Transformer Noise Reduction Frequency [Hz] 120 240 360 480 OA, dB (A) Conventional Transformer Noise, dB (A) 53 60 75 67 79 Noise after sound absorption baffle installation, dB (A) 41 41 45 45 64 Noise reduction (dB) 12 19 30 22 15

12 is a view showing an actual construction scene.

In the present invention, it is limited to reduce the noise of the transformer, but the technical idea of the present invention can be used to control the noise of machinery other than the transformer, one embodiment of the present invention is to reduce the 120Hz and 240Hz of the transformer However, it is natural that the structure can be appropriately changed for the purpose of reducing the noise component of the main component of the transformer or 360Hz noise component of the transformer.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, the scope of the present invention is not limited to these embodiments, and the scope of the present invention is defined by the following claims, and equivalent scope of the present invention. It will include various modifications and variations belonging to.

The reference numerals set forth in the claims below are merely to aid the understanding of the present invention, not to affect the interpretation of the scope of the claims, and the scope of the claims should not be construed narrowly.

1 is a schematic diagram of an indoor substation.

2 is a perspective view of a state in which a sound absorbing and resonating acoustic baffle for reducing transformer noise according to an embodiment of the present invention is installed;

3 is a plan view of a state in which the sound absorbing and resonance acoustic baffles of FIG. 2 are installed;

4 is a front view of a state in which the sound absorbing and resonance acoustic baffle of FIG. 2 is installed;

5 is a schematic diagram of noise traveling along a sound absorbing baffle;

6 is a graph showing noise reduction characteristics by a general sound absorbing vertical baffle ( Noise and Vibration Control , Ch. 12, edited by Leo L. Beranek, McGraw-Hill Book Company)

Figure 7 is a detailed baffle for explaining the noise reduction process by the horizontal baffle according to the present invention.

8 is a graph showing the amount of noise reduction when the noise passes directly through the sound absorbing transverse baffle (Reference: Noise and Vibration Control , Ch. 10, edited by Leo L. Beranek, McGraw-Hill Book Company)

9 is an indoor substation transformer noise measured at a certain point outside the wind before the sound absorption and resonance acoustic baffle of the present invention is installed.

10 is an indoor substation transformer noise measured at the same point as the measuring point of FIG. 9 after the sound absorbing and resonance acoustic baffle of the present invention is installed.

11 is a flowchart illustrating a method for installing a sound absorbing and resonating acoustic baffle of the present invention.

12 shows an actual construction scene.

<Description of the symbols for the main parts of the drawings>

1: transformer

2: substation floor

3: lower wind

4: upper wind

10: vertical baffle

15: air passage

20, 22, 23, 24: horizontal baffle

D: spacing between vertical baffles

W1: horizontal baffle width

Claims (8)

In the wind baffle for damping transformer noise, It has a plurality of vertical baffles 10 which are erected at a predetermined interval D perpendicular to the ground, and have a width W1 smaller than the distance D between the vertical baffles 10 and is horizontally between the vertical baffles 10. Sound absorption and resonance-type acoustic baffle for transformer noise reduction, characterized in that it comprises a plurality of horizontal baffles (20) installed in the. The method of claim 1, An interval between the horizontal baffles 20 installed in the upper and lower layers is 600 to 900 mm or 300 to 450 mm, the sound absorption and resonance acoustic baffle for transformer noise reduction, characterized in that it comprises one. According to claim 1, An interval between the horizontal baffles 20 installed in the upper and lower layers corresponds to one of 1/4 length of 120 Hz noise wavelength and 1/4 length of 240 Hz noise wavelength. baffler. The method of claim 1, The horizontal baffle 20 is provided with three horizontal baffles 22, 23, 24 as an upper and a lower layer between the vertical baffles 10 facing each other. The distance between the first horizontal baffle 22 and the second horizontal baffle 23 adjacent thereto is 600 to 900 mm, A sound absorption / resonance acoustic baffle for reducing transformer noise, wherein an interval between the second horizontal baffle 23 and the third horizontal baffle 24 located on the opposite side of the first horizontal baffle 22 is 300 to 450 mm. The method according to any one of claims 1 to 4, Sound absorbing and resonating acoustic baffle for transformer noise reduction, characterized in that the horizontal baffle (20) is provided with a resonator (30) tuned to a frequency selected from 120Hz and 240Hz. The method of claim 1, The interval between the horizontal baffles 20 provided in the upper and lower layers is the wavelength λ × (1/4) × 0.8 of the target target frequency noise λ × (1/4) × 1.2 of the target target frequency noise. Sound absorption / resonance type acoustic baffle for reducing transformer noise, which is included in the length range. In the wind baffle installation method for damping transformer noise, Installing a plurality of vertical baffles 10 at a predetermined interval D perpendicular to the ground; And horizontally installing a plurality of horizontal baffles 20 having a width W1 smaller than an interval D between the vertical baffles 10 between the vertical baffles 10. The interval between the horizontal baffle (20) is installed in the upper and lower layers, the sound absorbing and resonance-type acoustic baffle installation method for transformer noise reduction, characterized in that it comprises one selected from 600 to 900 mm or 300 to 450 mm. The method of claim 7, wherein Prior to installing 110 a plurality of longitudinal baffles 10, A step (105) of installing a frame (5) to support and fix the baffle to the airway; And a step (108) of installing the resonator (30) tuned to one of the frequencies of 120 Hz and 240 Hz in the horizontal baffle (20).

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