• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2223-2225
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• 2005

In this work, experimental investigation has been mainly done. For this purpose, UHF sensor has been designed and fabricated to detect the partial discharges produced from the 10 artificial defects introduced into the real scale 70kV GIS mock-up under the high voltage at the well shielded room. And also, in order to verify the applicability of the proposed method at the site, the proposed CAPD (chaos analysis of partial discharge) is combined with spectral analysis method in order to identify the nature of the above 10 defects. The PD pattern recognition of each defect has been fulfilled by applying self developed artificial neural network soft ware. The result shows that the recognition rate is reached to be 80% by newly proposed method while the traditional PRPD analysis method leads us to obtain 41%. In consequence, it can be pointed out that the proposed method seems likely to be applicable to the real GIS at the site.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2290-2292
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• 1999

The Ultra-High Frequency(UHF) method for detecting a partial discharge in Gas-Insulated Substation(GIS) has some advantages compared to a conventional method(IEC 270) but there is a shortage in view of a quantitative analysis. Therefore, this paper describes the implementation of a calibrator and the calibration process based on it. And its characteristics are confirmed through the experiment using the 362kV GIS chamber.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.467-467
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• 2007

Solid insulation exposed to voltage is degraded by electrical tree process. And the degradation of the insulation is accelerated by voltage application. For this experimental, specimen of electrical tree model is made by XLPE (cross-linked polyethylene). And the size of the specimen is $7^*5^*7mm^3$. Distance between needle and plane is 2 mm. Voltages applied to acceleration test are ranged 12 to 15 kV. And distribution characteristic of degraded stage is studied too. By PD detecting and data processing, discharge data was acquired from PD detecting system (Biddle instrument). The system presents statistical distribution of phase resolved. Moreover, the processing time of electrical tree is recorded to know the speed of degradation according to voltage. Finally, it's used PD classification by ANFIS method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.464-465
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• 2007

Solid insulation exposed to voltage is degraded by electrical tree process. And the degradation of the insulation is accelerated by voltage application. For this experimental, specimen of electrical tree model is made by XLPE (cross-linked polyethylene). And the size of the specimen is $7*5*7\;mm^3$. Distance of needle and plane is 2 mm. Voltages applied for acceleration test are 12 kV to 15 kV. And distribution characteristic of degraded stage is studied too. As a PD detecting and data process, discharge data acquire from PD detecting system (Biddle instrument). The system presents statistical distribution as phase resolved. Moreover the processing time of electrical tree is recorded to know the speed of degradation according to voltage.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1375_1377
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• 2009

PD의 저항성은 에폭시원형을 포함한 3종류 즉, 에폭시 마이크로 콤포지트를 실란처리 및 미처리한 경우 그리고 나노-마이크로입자가 혼합된 콤포지트의 부분방전저항성을 연구하였다. 이들 재료들은 rod - gap - plane 전극 하에서 PD가 적용되었다. 원형에폭시수지보다 마이크로 콤포지트가 부분방전저항성이 우월하였다. 더욱이 SiO2 나노입자-마이크로 혼합된 콤포지트가 더욱더 큰 저항성을 얻었다. 이는 마이크로 입자사이로 나노입자가 치밀한 조직을 갖고 있기에 이러 우월한 특성을 나타낸 것으로 판단된다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1788-1794
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• 2011

The mold transformer is a complex and critical component of DC substations in Metro system. In this paper, a cost effective and intelligent condition monitoring system for mold transformers in DC substations was developed. This paper also provides an overview of the management program using PD (partial discharge) data on mold transformers. Prior to application of the proposed system to Metro DC substations, experiments were performed at the metro line substation located in Seoul and presented case studies for the use of the intelligent condition monitoring system for mold transformer in DC substations. The experiment results indicated that the developing system can be need in helping mange the risk of unexpected failure of mold type transformers.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1715-1717
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• 2001

The partial-discharge(PD) is accompanied by physical and chemical phenomena, such as heat, light, noise gas, chemical transformation, electric current, and electromagnetic radiation. The PD can be detected by measuring one of these changes. Although some techniques are employed in this purpose, several obstacles interfere with an on-line measurement. Now, a fiber-optic sensor for detecting ultrasonics is suggested for the on line measurement system with high accuracy. This paper describes the basic principles fiber-optic sensor for ultrasonic measurement.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2000.11a
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• pp.241-245
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• 2000

In this paper, VHF(30~230[MHz]) electromagnetic waves radiated from partial discharge(PD) at two-type electrodes in air are measured and the peculiar patterns of their spectra are reported. Also, the polarization and distance characteristics of electromagnetic wave rediated by PD, were investigated. In case of epoxy insulator in inserted, the noise level of radiated electromagnetic waves is 0.6~6.2[dB] higher than the case in air at below 90[MHz]. The frequency spectrum distribution of radiated electromagnetic waves appears different in the whole frequency range according to the arrangement of antenna.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1871-1873
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• 2002

Partial Discharge is radiated in the form of electromagnetic wave from variable sources. It can be taken by UHF antenna and the signal pulse from that has a nonstationary time-series which can be evaluated with several methods. One of them is STFT(short time fourier transform) processed in frequency region. Statistical results using STFT show the possibility being able to discriminate between several PD sources.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1081-1083
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• 1999

The capacitive coupling technique has been used as conventional method for PD detection on the power cable line. Recently, however PD measurement using by high frequency is known to have an excellent sensitivity comparison with low frequency on-site. In this paper, the high frequency characteristic of two type of metal foil sensor was studied and the technique was proved to be more effective diagnostic method than conventional method for qualification of EHV cable and accessories.