• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.251-254
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• 2004

The aging diagnosis technique using partial discharge detection method detects partial discharge signals cause of power equipment failuer and able to forecast the aging state of insulation system through analysis algorithm, in this paper accumulates HFPD signal during constant scheduled cycles to build HFPD pattern and then analyzes HFPD pattern using statistical parameters and ${\Delta}F$ pattern. The 3D pattern is composed of detected signal frequency, amplitude and repeated number and the FRPDA(frequency resolved partial discharge analysis) technique is used in 3D pattern construction. The ${\Delta}F$ pattern shows variation characteristics of amplitude gradient of consecutive HFPD signal Pulses and able to classify discharge types-internal discharge, surface discharge and coronal discharge etc. Fractal mathematics applied to ${\Delta}F$ pattern quantification and neural networks is used in aging diagnostic algorithm.

• 전기학회논문지
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• 제58권10호
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• pp.2000-2004
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• 2009

In general, for the condition monitoring of a power transformer using the UHF PD measuring technique, detection of any partial discharge, identifying the defect in the transformer and locating the insulation defect are necessary. In this paper one of the most frequent detects which can result in turn to turn fault in power transformer was examined for identifying the defect. In order to model the defect, as a discharge source, a partial discharge cell was used for experimental activity. Magnitude of electromagnetic wave signals and corresponding amount of apparent discharge were measured simultaneously against phase of applied voltage to the discharge cell. Frequency range and phase resolved partial discharge signals were measured and analyzed. The results will be contributed to build the defect database of power transformer and to decrease the occurrence of transformer faults.

• 한국조명전기설비학회지:조명전기설비
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• 제9권6호
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• pp.65-70
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• 1995

본 논문에서는 부분방전에 의해 발생되는 초음파를 이용하여 변압기 절연성능을 예방진단하기 위하여 실 변압기 구조물이 있을 경우에 변압기 고압권선의 표면과 철심사이에서 초음파를 임의로 발생시킨 후 변압기 외함에서 초음파 신호 측정 시스템으로 이를 검출하여 분석함으로써 실 변압기에 적용시킬 경우 발생될 수 있는 문제점에 대하여 연구하였다. 실 변압기에서 구조물이 있을 경우에 고압권선의 표면이나 권선과 철심 사이에서 발생되는 초음파 탐촉자의 위치를 적절히 선정함으로써 변압기 외함에서 측정 가능하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.136-138
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• 2000

This paper describes an efficient location detection algorithm for a partial discharge(PD) source in the transformer. The algorithm is previously proposed is not suitable for PD source detection because ultrasonic signal is diminished through the inner structure. In this paper, the proposal algorithm find PD source using geometry method and 3th sensor on the one side of transformer without diminution of ultrasonic signal. The proposed algorithm demonstrates the effectiveness and validity on model transformer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.217-219
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• 2005

To detect partial discharge of 154kV joint box, we have made experiment by using the HFCT sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied with both noises of high voltage and noises of surrounding power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we test reliability on both injection of calibration signal in NJB and removal of low frequency. After that, we had analyzed frequencies by measuring signals in IJB with 300[m] distance from NJB. Also we had measured S/N ratio by using the indirected injection method of calibration signal in IJB. In this experiment, two measurement methods were difference of detection acquisition, but these had the equal frequency properties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기설비전문위원
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• pp.75-78
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• 2007

To detect partial discharge of 154kV joint box, we have made experiment by using the HFCT sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied with both noises of high voltage and noises of surrounding power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we test reliability on both injection of calibration signal in NJB and removal of low frequency. After that, we had analyzed frequencies by measuring signals in IJB with 300[m] distance from NJB. Also we had measured S/N ratio by using the indirected injection method of calibration signal in IJB. In this experiment, two measurement methods were difference of detection acquisition, but these had the equal frequency properties.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1999년도 학술대회논문집-국제 전기방전 및 플라즈마 심포지엄 Proceedings of 1999 KIIEE Annual Conference-International Symposium of Electrical Discharge and Plasma
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• pp.136-140
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• 1999

Measurements of AE signals caused by partial discharges were performed by using an ultrasonic measurement technique to diagonise the electrical treeing deterioration in XLPE cable. We also examined the partial discharge magnitude and AE signals(peak-to-peak) with the increase of the deterioration time. From these results, it was found that AE signal due to partial discharge can be greatly detected at the peak value of positive polarities prior to the breakdown voltages, and the magnitude of AE signals was closely related to the current pulses by the increase of deterioration, and it appeared that AE signals(peak-to-peak) was proportional to partial discharge magnitude. Attenuation and time-delaying characteristics of ultrasonic signals propagated in various polymers sample by using ultrasonic oscillation and receiving systems are also reported as a basic data of ultrasonic measurements in XLPE cable.

• 전기학회논문지
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• 제63권10호
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• pp.1461-1466
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• 2014

GIS(Gas Insulated Switchgear) is important power apparatus which have strong dielectric strength, supply electric power and is a part of the power system. Most substation type is configured as GIS. Recently, because of continuous increasement of GIS demand resulted from high quality & big capacity of electric power, the necessity of the preventive & diagnosis system is being expanded gradually. GIS partial discharge occurred on the UHF band is detected effectively by the method to IEC 60270 that recommend to be able to detect the apparent minimum discharge, 5 pC. Additionally, the UHF sensor should be installed to detect PD signal if Partial discharge signal, 5 pC occur in every part of GIS. Currently PD diagnosis system applying UHF sensor for GIS with various voltage level like 154 kV, 345 kV, 765 kV have been operated. And it is necessary to measure and analyze insulation breakdown phenomenon of inside GIS exactly. In this paper, we proposed Fat-dipole patch UHF sensor that is developed and more sensitive, excellent wide-range characteristic than the exising UHF sensor. And we performed KERI (Korea Electrotechnology Research Institute) reference test, which showed the excellent result for the all tests.

• 전기학회논문지
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• 제57권12호
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• pp.2300-2307
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• 2008

This study receives the noise transmitted in a constant audio frequency range through a microphone array in which the noise(like grease in a pan) occurs on the power supply line due to the troublesome partial discharge(arc). Then by going through a series of signal processing of removing noise, this study measures the distance and direction up to the noise caused by the troublesome partial discharge(arc) and monitors the result by displaying in the analog and digital method. After these, it determines the state of each size and judges the distance and direction of problematic part. When the signal sound transmitted by the signal source of bad insulator is received on each microphone, the signal comes only in the frequency range of 20 kHz by passing through the circuit of amplification and 6th low pass filter. Then, this signal is entered in a digital value of digital signal processing(TMS320F2812) through the 16-bit A/D conversion. By doing so, the sound distance, direction and coordinate of bad insulator can be detected by realizing the correlation method of detecting the arriving time difference occurring on each microphone and the algorithm of detecting maximum time difference.

• 한국전기전자재료학회논문지
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• 제19권2호
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• pp.162-168
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• 2006

Recently, diagnosis techniques have been investigated to detect a Partial Discharge associated with a dielectric material defect in a high voltage electrical apparatus, However, the properties of detection technique of Partial Discharge aren't completely understood because the physical process of Partial Discharge. Therefore, this paper analyzes the process on surface discharge of polymer insulator using wavelet transform. Wavelet transform provides a direct quantitative measure of spectral content in the time~frequency domain. As it is important to develop a non-contact method for detecting the kaolin contamination degree, this research analyzes the electromagnetic waves emitted from Partial Discharge using wavelet transform. This result experimentally shows the process of Partial Discharge as a two-dimensional distribution in the time-frequency domain. Feature extraction parameter namely, maximum and average of wavelet coefficients values, wavelet coefficients value at the point of $95\%$ in a histogram and number of maximum wavelet coefficient have used electromagnetic wave signals as input signals in the preprocessing process of neural networks in order to identify kaolin contamination rates. As result, root sum square error was produced by the test with a learning of neural networks obtained 0.00828.