• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.3
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• pp.84-90
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• 2014

The partial discharge of Cast-resin Transformer has a difficulty to be analyzed, because it is an abnormal condition signal of which stochastic characteristics varies with time variance. In this study, background noise coming from the outside of the cast-resin transformers through ground wire can be removed and only a discharge signal of which defects are simulated can be obtained, using the wavelet transform method, which is a time-frequency domain analysis technique. As a result, it was confirmed that de-noising using the SWT technique is the best efficient among three methods of the wavelet transform techniques.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.828-829
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• 2015

본 논문은 몰드 변압기의 PD(Partial Discharge) 발생 여부를 판단하기 위해 Wavelet Transform을 이용한 PD 신호의 De-Noising에 관한 연구이다. PD는 변압기 고장사고 중 가장 판단하기 어렵고, 예방 및 진단 시 적은 항목의 검사 항목을 통해 관리되어진다. 따라서 보다 정확하게 PD 발생 여부를 판단하는 것이 중요하다. 본 논문에서는 몰드 변압기의 PD 신호를 측정하고, 취득한 신호를 Wavelet Transform을 이용한 De-Noising을 수행하고 몰드 변압기의 PD 발생여부에 대해 확인하는 방법에 대한 연구를 수행하였다.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1487-1496
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• 2013

In this paper, a novel algorithm for PD localization in power transformers based on wavelet de-noising technique and energy criterion is proposed. Partial discharge is one of the main failures in power transformers. The localization of which could be very useful for maintenance systems. Acoustic signals due to a PD event are transient, irregular and non-repetitive. So wavelet transform is an efficient tool for this signal processing problem that gives a time-frequency demonstration. First, different wavelet based de-noising methods are analyzed. Then, a reasonable structure for threshold value determining and applying manner on signals is presented. Evaluated errors are good evidences for choices. Next, applying the elimination low energy frequency bands is discussed and developed as a de-noising method. Time differences between signals are used for PD localization. Different ways in time arrival detection are introduced and a novel approach in energy criterion method is presented. At the end, the quality of algorithm is verified through the different assays in lab.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.404-406
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• 2001

This paper is detecting a partial discharge(PD) using antenna. The wavelet transform is applied for the analysis of PD pulse signal. It is difficult to identify PD signal using electromagnetic waves detected by antenna. And so we can removed noise of PD signal using wavelet de-noising method.