• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.215-216
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• 2005

To decrease and remove of much noises that is detected in PD (partial discharge) measuring test. we forced on detection of those. We made W-LC filter for measuring PD. which adapted that to field test. We tested after design laboratory circumstances like field line. and then the phase change properties of detected signal in UHF sensor were measured by Lemke Probe and oscilloscope (TDS-3054. Tektronix). Eventually we checked decrement of noises from experimental result. Also from experimental result at the joint box of 22.9[kV] distribution line. we obtained reasonable data which enable noises to decrease. Hereafter those results will be adapted at ultra-high voltage for trouble prevention and on-line cable watch. diagnosis of those.

• 전기학회논문지P
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• 제56권3호
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• pp.123-128
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• 2007

Hydro power supplies no pollution energy, mainly induction generator has been applied at the small capacity power station. The generating power of small hydro-electric power station connects on the 22.9kV distribution system or low voltage system in the case of three-phase four-wire supply system. There are side effects of various kinds in the 3-three phase 4-wire distribution system mixing 1-phase load and 3-phase load. This system generates the voltage unbalance by unbalanced load operating condition. They have various serious effects on generator and connection system. In this paper, we analyzed what kind of operation characteristic are happened in the induction generator by customer load variation at the 3-three phase 4-wire distribution system.

• 조명전기설비학회논문지
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• 제23권1호
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• pp.85-91
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• 2009

본 논문에서는 배전계통에 사용되는 케이블 권선형 변압기에 전력계통에서 발생되는 서지나 고장전류에 의해서 변압기의 고압측 코일에 유도되는 전자력의 크기를 유한요소 전자계해석 프로그램(FLUX2D)을 이용하여 해석하고, 기계진동방정식을 이용하여 케이블형 권선의 고유진동주파수를 분석하였다. 변압기모델로서 1(MVA), 22,900/220([V]) 단상 외철형 Cable형을 선정하여, 권선의 각방향의 전자력을 분석하고, 고유진동 mode를 Transfer Matrix Method를 이용하여 계산하고 상용 프로그램(ANSYS)을 이용하여 분석한 결과와 비교하였다. 진동모드의 분석한 결과 제시한 수치해석 방법은 공학적인 오차범위 안에서 충분히 수용할 정도의 정확도를 보여주었다. 변압기 권선의 전자력과 진동모드 분석결과는 변압기의 절연설계 및 단락기계력에 의한 절연 구조 설계를 위한 유용한 자료로 활용될 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기설비전문위원
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• pp.218-221
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• 2008

Due to a variable noises in the field underground lines, clear technology of noises is very important in the diagnosis technology of partial discharge. Therefore we progressed filter test to improve the measuring test of partial discharge in a field. We applied to field test after making W-LC filter for partial discharge measurement, and then designed experimental environment such as under- ground distribution lines of field. Measuring sensor for test was UHF sensor. And we analysed those using the Lemke Probe and oscilloscope (TDS-3054, Tektro- nix). Finally, we obtained excellent data of noise decrement in the joint box of 22.9[kV] distribution lines from above experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.74_76
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• 2009

This paper presents a discrete wavelet analysis based algorithm to address the fault impedance calculation under transient state in radial power distribution networks. The fault impedances have been derived under different fault conditions. Furthermore, a recursive fault distance estimation method is proposed utilizing the measured fault impedance and power line parameters. The proposed scheme can resolve the errors caused by the non-homogeneous power lines, the presence of lateral loads since, the fault impedance will always be updated with the recursive form. For the verification of the proposed scheme, a filed test has been peformed with varying fault resistances in the 22.9(kV) radial system. Power meters and fault locators were installed at the substation. It was figured out that the performance of the discrete wavelet and the recursive scheme are very good even for high fault resistance condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.46-48
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• 2007

This paper presents research about improvement of fault detection algorithm in FRTU on the feeder of distribution system. FRTU(Feeder Remote Terminal Unit) is applied to fault detection schemes for phase fault, ground fault, and cold load pickup and Inrush restraint functions distinguish the fault current and the normal load current. FRTU is occurred FI(Fault Indicator) when current is over pick-up value also inrush current is occurred FRTU indicate FI. Discrete wavelet transform(DWT) analysis gives the frequency and time-scale information. The neural network system as a fault detector was trained to discriminate inrush current from the fault status by a gradient descent method. In this paper, fault detection is improved using voltage monitoring system with DWT and neural network. These data were measured in actual 22.9kV distribution system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2228-2230
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• 2002

The research presented in this paper focuses on a method for the detection of High Impedance Fault(HIF). The method will use the Lifting and neural network system. HIF on the multi-grounded three-phase four-wires primary distribution power system cannot be detected effectively by existing over current sensing devices. These paper describes the application of lifting scheme to the various HIF data. These data were measured in actual 22.9kV distribution system. Wavelet transform analysis gives the frequency and time-scale information. The neural network system as a fault detector was trained to discriminate HIF from the normal status by a gradient descent method. The proposed method performed very well by proving the right state when it was applied staged fault data and normal load mimics HIF, such as arc-welder.

• 한국안전학회지
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• 제33권3호
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• pp.21-26
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• 2018

Approximately 20% of the total fire is electrical fire, and electrical energy is a potential source of heat. Large-scale fault currents that occur during a line ground fault flow into electric utility poles, electric power equipment, or electric appliances of the customer, and cause simultaneous electrical fire. In this paper, we investigated the possibility of fire through the change of fault current flowing in faulty and sound feeder in case of 1 line ground fault in 22.9 kV distribution line. We propose a fire investigation analysis method for simultaneous multiple electrical fire such as evidence analysis method, and fault current occurrence confirmation method in case of fire accident by analyzing the fault current occurring in the ground fault in the distribution line using EMTP, electric power system analysis program.

• 대한전기학회논문지:전력기술부문A
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• 제49권6호
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• pp.280-288
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• 2000

Recently, there has been growing interest in utilizing cogeneration(COGN) systems with a high-energy efficiency due to the increasing energy consumption and the lacking of energy resource. But an insertion of COGN system to existing power distribution system can cause several problems such as voltage variations, harmonics, protective coordination, increasing fault current etc, because of reverse power of COGN, especially in protective coordination. A study on a proper coordination with existing one is being required. The existing power distribution system is operated with radial type by one source and protection system is composed based on unidirectional power source. But an Insertion of COGN system to power distribution system change existing unidirectional power source system to bidirectional power source. Therefore, investigation to cover whole field of power distribution system must be accomplished such as changing of protection devices rating by increasing fault current, reevaluation of protective coordination. In this paper, simulation using PSCAD/EMTDC was accomplished to analyze effect of COGIN on distribution fault current. Also, the existing protection system of 22.9[kV] power distribution system and customers protection system to protect of COGIN was analyzed and the study on protective coordination between of two protection system accomplished.

• 생명과학회지
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• 제20권9호
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• pp.1287-1293
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• 2010

RAPD에 의한 지리산 내 산거울 집단의 유전자 빈도와 지리적 거리에 따른 공간적 상관관계를 분석하였다. 전체 102 DNA 분절(밴드)이 107 개체에서 탐지되었다. 102 밴드 중 48(47.1%)개 밴드는 다형성을 나타내었다. 분집단간 다형성의 비교에서 거리 구간 I와 V가 가장 낮은 변이(16.7%)를 나타내었고, 거리 구간 VIII이 가장 높은 변이를 나타내었다(22.6%). 전체 다양도는 0.076이었다. 구간 VIII이 가장 높은 다양도(0.093)를 나타내었고, 구간 I가 가장 낮았다(0.063). 구간 사이의 유전적 유사도는 60 m 거리까지는 유사하였다. 지리산 집단에서 산거울은 강한 공간구조를 나타내고 있음이 RAPD 마커로 알 수 있었다. 이는 지리산 집단에서 낮은 이주자수와 개체들이 덩어리 모양의 분포를 나타내기 때문으로 판단된다. 본 연구에서 RAPD 마커로 산거울의 공간구조와 유전적 구조를 파악하는데 유용하게 이용될 수 있음을 입증하였다.