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변압기내 결함의 종류에 따른 부분방전의 초음파신호 특성 분석
박현수(Park Hyun-Soo),진상범(Chin Sang-Bum),곽희로(Kwak Hee-Ro),권동진(Kweon Dong-Jin),박하용(Park Ha-Yong) 한국조명·전기설비학회 1999 한국조명·전기설비학회 학술대회논문집 Vol.1999 No.-
Out of the defects occurred in a transformer, the cases of protrusion and surface discharge were simulated by using needle-plane and IEC(B) electrode. The waveform and frequency characteristics of ultrasonic signals due to partial discharge occurred at each electrode were analyzed. And then, the ultrasonic signal characteristics from the partial discharge due to the two kinds of defect were compared. As a result, in the case of the protrusion and surface discharge, the waveforms were similar, but the frequency spectra were different.
곽동걸,김춘삼,박하용,심재선,심상흥,Kwak, Dong-Kurl,Kim, Choon-Sam,Park, Ha-Yong,Shim, Jae-Sun,Shim, Sang-Heung 한국조명전기설비학회 2005 조명·전기설비학회논문지 Vol.19 No.7
본 논문은 전류불연속 제어에 의한 고역률, 고효율로 동작되는 승압형 AC-DC 컨버터에 대해 연구된다. 전류불 연속 제어 컨버터는 제어회로 구성이 간단하고 구성소자의 수를 줄일 수 있는 장점을 가진다. 제안된 컨버터의 입력전류는 듀티율 일정제어에 의한 교류 입력전압의 크기에 비례된 불연속적인 정현파 형태로 된다. 그 결과 입력역률은 거의 단위역률로 주어지며 듀티율 일정제어에 의해 제어기법이 간단하다. 또한 제안된 컨버터의 스위칭 소자들은 부분공진 기법에 의해 소프트 스위칭 동작으로 되어 스위칭 손실이 매우 낮으며 컨버터의 효율을 증대시킨다. 부분공진 회로부는 승압용으로 사용된 인덕터와 무손실 스너버 커패시터에 의해 설계되어 컨버터의 회로 토폴로지가 간단하다. 제안된 컨버터는 컴퓨터 시뮬레이션과 실험결과에 의해 그 타당성이 입증된다. This paper is studied on boost AC-DC converter of high power factor and high efficiency for discontinuous current control. The converter operated in discontinuous current control eliminates the complicated circuit control requirement, and reduces a number of components. The input current waveform in proposed circuit is got to be a discontinuous sinusoidal form in proportion to magnitude of ac input voltage under the constant duty cycle switching. Therefore, the input power factor is nearly unity and the control circuit is simple. Also the switching devices in a proposed circuit are operated with soft switching by the partial resonant method. The result is that the switching loss is very low and the efficiency of system is high. The partial resonant circuit makes use of a inductor using step up and loss-less snubber capacitor. The circuit topology of the converter is simplified. Some simulative results on computer and experimental results are included to confirm the validity of the analytical results.
분포통계모델에 의한 가교폴리에틸렌 절연체의 부분방전 패턴해석
김탁용,박희두,조경순,박하용,홍진웅,Kim Tag-Yong,Park Hee-Doo,Cho Kyung-Soon,Park Ha-Yong,Hong Jin-Woong 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.10
It has been confirmed that the inner defect of insulator and the perfect diagnosis for aging are closely related to safe electric power transmission system and that the detection of accident and diagnosis technique turn out to be very important issues. But perfect diagnosis is difficult because discharge pattern is irregular. Thus, we investigated discharge pattern using the new distribution statistical models with cross-inked polyethylene(XLPE) specimens. Voltage was applied to power frequency by step method, and calibration of discharge was set to 50 pC. After the voltage was applied, it measured the discharge occurring during 10s. We investigated discharge pattern using the K-means analysis and Weibull function. We also investigated variation of centroid and shape parameter due to variation of voltage. As a result of analyzing K-means, it was confirmed that cluster including many object numbers was formed by the presence of void. And result of Weibull distribution, it was confirmed that shape parameter of discharge varied from 1.28 to 1.62 in no void specimens, and that shape parameter of discharge number varied from 1.28 to 1.62. In the void, shape parameter of discharge varied from 5.66 to 6.43, and shape parameter of discharge number varied from 5.05 to 5.08.