• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2011년도 춘계학술발표대회 논문집
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• pp.119-123
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• 2011

Through the test of ESD(Electro Static Discharge) for PCB circuit, we are able to research on the ESD effect. This paper also study on the ESD test method for measurement. It is interesting to compare their characteristics on and the other method.

• 조명전기설비학회논문지
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• 제17권2호
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• pp.81-87
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• 2003

본 논문은 공기중 침대 평판 전극계를 이용하여 방전진전 과정과 부분방전을 모의하였다. 이 때 방전진전과정에 따른 방사전자파를 biconical 안테나와 스펙트럼 분석기를 이용하여 주파수 스펙트럼 분포를 분석 연구하였다. 본 연구의 결과로부터 공기중 교류방전 진전에 따른 방사전자파의 측정과 분석에 의한 절연진단을 위한 방법을 제시하였고 또한 방전진전과정과 방사전자파를 상호관계를 고려하면 부분방전의 검출과 방전진전과정의 평가가 가능함을 확인하였다

• 대한기계학회논문집B
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• 제27권9호
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• pp.1248-1255
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• 2003

Pressure coefficient in a rotating discharge hole was measured to gain insight into the influence of rotation on the discharge characteristics of rotating discharge holes. Pressures inside the hole were measured by a telemetry system that had been developed by the authors. The telemetry system is characterized by the diversity of applicable sensor type. In the present study, the telemetry system was modified to measure static pressure using piezoresistive pressure sensors. The pressure sensor is affected by centrifugal force and change of orientation relative to the gravity. The orientation of sensor installation for minimum rotating effect and zero gravity effect was found out from the test. Pressure coefficients in a rotating discharge hole were measured in longitudinal direction as well as circumferential direction at various rotating speeds and three different pressure ratios. From the results, the behaviors of pressure coefficient that cannot be observed by a non-rotating setup were presented. It was also shown that the discharge characteristics of rotating discharge hole is much more influenced by the Rotation number irrespective of pressure ratio.

• 한국수자원학회논문집
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• 제44권5호
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• pp.377-388
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• 2011

표면영상유속계(SIV)는 영상 분석 기법을 이용하여 하천의 표면유속을 측정하고, 이를 토대로 유량을 산정하는 시스템이다. 본 연구에서는 고정식 표면영상유속계(FSIV) 시스템을 달천 수전교에 설치하여 실시간으로 연속적인 유량 측정을 실시하였다. 수전교에 적용된 FSIV의 하드웨어 시스템은 영상 획득을 위한 2대의 디지털 카메라와 컴퓨터, 그리고 수위 측정을 위한 초음파 수위계로 구성된다. 이 현장 장비들에서 획득된 실시간 영상과 수위 자료는 무선인터넷을 이용하여 실시간으로 홈페이지에 전송되며, 표면영상유속분석 소프트웨어를 이용하여 유량을 산정한다. FSIV에 의한 유량산정 결과는 직상류의 괴산댐 방류량과 FSIV와 동일한 지점에 설치된 Acoustic Doppler Velocity Meter (ADVM)를 설치한 후 유속지수법으로 산정된 유량과 비교하여 검토하였다. 댐 방류량과 비교한 결과 30$m^3/s$ 이상의 유량에서는 대부분 5~10%의 오차를 보였으며, ADVM을 이용하여 측정된 유량과 비교한 결과는 약 200$m^3/s$ 이상의 유량에서는 오차가 약 5 % 이내로 확인되었다. FSIV의 설치 경비와 운용에 드는 비용과 인력을 감안한다면, FSIV는 실시간으로 유량을 관측할 수 있는 좋은 대안이 될 것으로 판단된다.

• Transactions on Electrical and Electronic Materials
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• 제14권4호
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• pp.211-215
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• 2013

Partial discharge diagnosis techniques using ultra high frequencies do not affect load movement, because there is no interruption of power. Consequently, these techniques are popular among the prevention diagnosis methods. For the first time, this measurement technique has been applied to the GIS, and has been tested by applying an extra high voltage switchboard. This particular technique makes it easy to measure in the live state, and is not affected by the noise generated by analyzing the causes of faults ? thereby making risk analysis possible. It is reported that the analysis data and the evaluation of the risk level are improved, especially for poor location, and that the measurement of Ultra high frequency (UHF) partial discharge of the real live wire in industrial switchgear is spectacular. Partial discharge diagnosis techniques by using the Ultra High Frequency sensor have been recently highlighted, and it is verified by applying them to the GIS. This has become one of the new and various power equipment techniques. Diagnosis using a UHF sensor is easy to measure, and waveform analysis is already standardized, due to numerous past case experiments. This technique is currently active in research and development, and commercialization is becoming a reality. Another aspect of this technique is that it can determine the occurrences and types of partial discharge, by the application diagnosis for live wire of ultra high voltage switchgear. Measured data by using the UHF partial discharge techniques for ultra high voltage switchgear was obtained from 200 places in Gumi, Yeosu, Taiwan and China's semiconductor plants, and also the partial discharge signals at 15 other places were found. It was confirmed that the partial discharge signal was destroyed by improving the work of junction bolt tightening check, and the cable head reinforcement insulation at 8 places with a possibility for preventing the interruption of service. Also, it was confirmed that the UHF partial discharge measurement techniques are also a prevention diagnosis method in actual industrial sites. The measured field data and the usage of the research for risk assessment techniques of the live wire status of power equipment make a valuable database for future improvements.

• 전기학회논문지
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• 제58권10호
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• pp.1995-1999
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• 2009

A partial discharge(PD) measurement is a very effective method to assess the insulation condition of high-voltage machines. It is necessary that the life time of the on-line PD measurement sensor is assessed. Therefore, the electrical life time assessment method of ceramic element was reviewed in order to estimate the life time of the on-line PD measurement sensor. The samples were prepared according to the reviewed method and were tested at 8kV, 9kV and 10kV. Based on the obtained results, the life time constant is shown above 59. Also, it is assumed that the estimated life time constant can be used to anticipate the life time and to assess the conformity of the on-line PD measurement sensor.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권4호
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• pp.189-198
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• 2006

In order to improve the reliability of stator windings for hydro generators, it is necessary to detect the defective point and life assessment of the high voltage windings. Especially the on-line partial discharge (PD) test provides the ability to monitor effects, such as slot discharge, internal discharge, and end-winding discharge without interrupting generators, this method has been proven the major testing technology in high voltage rotating machines nowadays. The purpose of this paper is to describe the method of the on-line PD measurement on stator windings for hydro-generator with 13 [kV] class ceramic coupler (CC), on-line PD measuring system, terminal box, and index parameters. Also, the developed PD measuring system and 13 [kV] class CC were installed Daechung-dam generator #2. It was found that this installed sensor and system had good electrical characteristics to detect PD activity during the operating condition with its detection frequency band is between several and several tens MHz.

• 전기학회논문지
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• 제61권2호
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• pp.251-256
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• 2012

This study deals with the location of partial discharges(PDs) for power cables and GIS using 2 PD sensors and long coaxial signal cables. Throughout the experiments by use of simulated PD pulses and corona discharges in the power cable system, it is found out that the impedance matching between the coaxial signal cable and the measuring equipment should be done for good S/N ratio and the on-site measurement using more than 100m-long coaxial signal cable is possible. In addition, new PD location algorithm with the polarities of PD pulses and the arrival time difference between two pulses was proposed and was proved through the partial discharge experiments for the cable joint defect and artificial void defect.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.149-149
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• 2012

We introduce Helicon discharge plasma source and Laser Thomson scattering system recently finished an installation in KRISS. Laser Thomson scattering method is promising for diagnostics in Helicon plasma because a measurement by electrical probe typically used has significant errors due to the gyromotion of electrons induced by high magnetic field. However, we found that LTS is affected by magnetic field so that we applied the normalization method for processing data and the results show a clear Maxwellian distribution at various conditions of magnetic field and RF power at low energy part without distortion.

• 환경위생공학
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• 제23권4호
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• pp.83-93
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• 2008

The non-linear least squares model(NLSM) has long been the standard technique used by hydrologists for constructing rating curves. The reasons for its adaptation are vague, and its appropriateness as a method of describing discharge measurement uncertainty has not been well investigated. It is shown in this paper that the classical method of NLSM can model only a very limited class of variance heterogeneity. Furthermore, this lack of flexibility often leads to unaccounted heteroscedasticity, resulting in dubious values for the rating curve parameters and estimated discharge. By introducing a heteroscedastic maximum likelihood model(HMLM), the variance heterogeneity is treated more generally. The maximum likelihood model stabilises the variance better than the NLSM approach, and thus is a more robust and appropriate way to fit a rating curve to a set of discharge measurements.