• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.10
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• pp.104-110
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• 2008

Desire about agreeable habitat by enhancement of standard of living has been increased, and common complaints by transformer noise have been happening constantly. It has been installed resonator and sound-proof shutter in order to solve substation's noise problems. But those methods are not effective. Therefore, It is necessary to study transformer noise level that can satisfy noise regulation standard. In this paper described that predicted transformer noise level of substation boundary by operating situation at the indoor substation. Also, Presented most suitable noise level of transformer that satisfy noise regulation standard at the indoor substations through predicted results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.12
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• pp.1032-1040
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• 2001

In order to apply the partial discharge measuring technique utilizing electrical pulse to the transformer at sites, this paper describes the measuring technique obtaining only the signals due to internal partial discharge in the transformer, but the noises due to external corona which has been a major problem so far. At first, partial discharge and corona noise were simultaneously generated in the model transformer by using needle-plane electrodes and rod-sphere electrodes out of it in a high voltage laboratory, respectively. It was verified that only the partial discharge signals in the transformer could be measured by removing the noise signals from the superposed signals of partial discharges and noises on the grounding wire of the model transformer. By application to a 345kV transformer in service, it was also confirmed that the partial discharge could be on-line monitored by removing the noise signals measured by the inductance sensor on the grounding wire of a 154kV lightning arrester from the superposed signals of internal partial discharge and external corona noise measured by bushing tap coupler of the transformer.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.8
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• pp.1382-1387
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• 2010

Recently, there has been a growing interest in the environmental conservation. Accordingly, problems related to the audible noise of transformers have became more frequent. Therefore, it is urgent to find a fundamental solution about the audible noises in the substations. This paper described a sort of fundamental solution to solve the noise problem. As a fundamental solution, we suggested the proper audible noise level of transformers through noise prediction in the substation construction phase. And we applied the low noise transformers which have the predicted noise level. As the result, we are able to satisfy the noise regulation through measuring 43.6dBA at the boundary of substation. It is confirmed that the average error rate of prediction was within 3 percent.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.112-116
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• 2007

Highly damped insulation panel for transformer construction is needed in residential area because the making noise from transformer substation in inner city is appeared a lost of problem by increasing to conserve living environment. Therefor in this paper, the vibration and noise characteristic effect of cork-type and sponge-type that is attached between insulation panel and enforce beam in transformer is analized using real size transformer experimentally.

• Journal of Power System Engineering
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• v.4 no.4
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• pp.59-64
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• 2000

Especially, demands for the noise reduction of mold transformer has been becoming an common issue because it has been used mainly at the residence area such as building and ship. So, this paper investigates the noise source and countermeasure of mold transformer radiated high noise abnormally. The result of impact hammering test for core of transformer ascertains the core resonance by harmonics of line frequency and high noise can be reduced to avoid core resonance by changing torque strength of tie rod. Magnetic field analysis is performed to identify the reason that noise of V-phase is higher than U and W-phase in the normal condition. It is the cause that flux density and magnetic force of V-phase is higher than the other phase respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.91-99
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• 2010

HVDC converter station consists of a number of equipment such as converter transformer, ac filter, thyristor valve and so on. They can be acoustic noise sources. In this paper, we analyzed the simulation results of the outdoor acoustic noise for HVDC converter station. It shows that maximum noise level in boundary of HVDC converter station exceeds regulation value. The main factors in generating maximum noise level are ac filter and converter transformer. Then we applied some soundproof countermeasures in HVDC converter station. Shielding wall is enough to reduce transformer noise level but not enough to reduce ac filter noise level. In case of ac filter, soundproof building is effective in satisfying noise level regulation in boundary of HVDC converter station. In addition, we also studied effects of season, soundproof woods, ground.

• Journal of KSNVE
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• v.9 no.6
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• pp.1137-1144
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• 1999

Most of ANC(active noise control) researches are focused on adaptive algorithms, computer simulations and implementations of single-channel system in experimental environments. In this paper, a multi-channel ANC system based on DSP's was developed to obtain global attenuations over wide region and applied to the active control of the humming noise generated by a transformer. The developed ANC system including 24 microphones and 12 spearkers was applied to the real transformer noise reduction problem. Results showed that the control system could successfully control the humming noise over the region of interest.

• The Journal of the Acoustical Society of Korea
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• v.43 no.3
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• pp.277-284
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• 2024

This study proposes a method to predict noise reduction based on noise-reduction measures, using harmonic response analysis, for transformer design. The dynamic elastic coefficients of the components comprising the actual transformer were determined by manufacturing the materials of the transformer components into simple-shaped specimens, followed by a comparison of the modes between the experiments and the analyses. A finite element model of the transformer was implemented, and harmonic response analysis was performed by deriving the exciting force of the transformer. Subsequently, the theoretical sound power level of the transformer was derived from the results of the harmonic response analysis. Finally, noise reduction measures were established, and the noise reduction amounts were compared between the experiments and the analyses, before and after applying the measures. Through the comparison and analyses of the noise reduction measures, it was confirmed that the trends in the experiments and analyses matched.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.513-518
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• 2003

Noises are defined as unwanted sound and invoke the physical harm and unconvenience. The higher the noise level is, the more damage peoples have. Low frequency noise is less harmful than high frequency one. In case of train, noises inside of train which is isolated from outer circumstances reduce the convenience of passenger very much. This paper reviewed the noise standard of train for urban subway and investigated the main transformer as the main noise source of train and suggested the method to diminish the noise resulted from main transformer of train and compared the measured results of before and after the improvement of main transformer.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1962-1969
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• 2008

According to the increase of power demand and expansion of downtown, it is necessary to install transformers additionally in operating substations and construct substations in residential area. But the public complaint is increased due to the transformer noise of the substation. KEPCO has used a vibration preventing pad, various soundproof walls and an encloser to transformers in outdoor substations, and a soundproof door, shutter and wind-path soundproof equipment in indoor substations to block the sound propagation of the transformers. But these noise reduction methods are not satisfied. It should be considered to reduce transformer noise itself. In this paper, we investigated core noise reduction techniques to develope a low noise transformer. The techniques to reduce core noise of the transformer are application of high permeability grain oriented silicon sheets, decrease of magnetic flux density of core, application of 6step-lap core stacking method, improvement of core binding method(binding addition, band fixing) and application of rubber damper in oder to reduce transmission of core vibration, etc.