http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
수상 태양광 발전설비의 구조체용 접지전극 설치 조건에 따른 전기적 특성 분석
김유하(Yoo-Ha Kim) 한국조명·전기설비학회 2020 조명·전기설비학회논문지 Vol.34 No.8
Currently, the exact electrical regulations for the grounding system of floating photovoltaic power generation systems have not been established. Due to the peculiarity of being installed on the water surface, the installation conditions of the ground electrode are different from that of the general photovoltaic power generation facility. Three cases can be installed where the ground electrode of the structure of the floating photovoltaic system is installed in the water, on the waterside, and on nearby land. In consideration of this case, the ground resistance was measured using a fall of potential method for a grounding method that can be applied to a photovoltaic power generation facility. Also, in the typical case, the transient potential rise value by the standard lightning current waveform was analyzed by CDEGS simulation. As a result, the grounding electrode installed in the water became the lowest grounding resistance value and exhibited the lowest transient potential rise. Since it can be installed in parallel due to the characteristics of the floating photovoltaic power generation facility, it is desirable to determine the installation location of the ground electrode in consideration of the electrical characteristics in each case.
PV 전류를 이용한 최대전력점 추적방식의 태양광 발전 시스템 개발
유양우(Yang-Woo Yoo),서덕현(Deok-Hyun Seo),김유하(Yoo-Ha Kim) 한국조명·전기설비학회 2014 조명·전기설비학회논문지 Vol.28 No.5
Maximum power point tracking method is very important to enhance efficiency of photovoltaic system. Meanwhile a lot of research about MPPT has been studied and developed new one better than a method of the past. This paper deals with Perturb and Observation that are most commonly used. Tracking parameter changed PV voltage for PV current and it was simulated with P-SIM program. The P&O tracking method to use current for parameter lows ripple rate of output and enhances response rate of tracking. Through this study, it has been demonstrated that method using current for tracking parameter is effective.
유양우(Yang-Woo Yoo),김승민(Seung-Min Kim),김유하(You-Ha Kim),이복희(Bok-Hee Lee) 한국조명·전기설비학회 2015 조명·전기설비학회논문지 Vol.29 No.4
This paper presents experimental results about characteristics of soil discharge as a function of moisture content when the 1.2/50㎲ lightning impulse voltage is applied. The laboratory experiments, for this study, were carried out based on factors affecting the transient behavior in soils. The electrical breakdown in soils was measured over a 0-6% range of moisture content for sands and a 0-4% range of moisture content for gravels. Needle-plane electrode systems was used As a result, the conduction current prior to ionization growth in dry soil is a little, but it in wet soil is increased with the applied voltage because the wet soil particles act as conductors. The soil impedance curves show an abrupt reduction just after breakdown. The general tendency measured in different soils is that the higher the water content, the lower the breakdown voltage and the shorter the time-lag to breakdown.
유양우(Yang-Woo Yoo),김승민(Seung-Min Kim),김유하(You-Ha Kim),이복희(Bok-Hee Lee) 한국조명·전기설비학회 2014 조명·전기설비학회논문지 Vol.28 No.10
This paper presents the results of model tests for the attachment process of lightning leader to ground which is one of poorly understood processes of cloud-to-ground lightning discharges. In order to simulate the attachment process of lightning leader to ground, we investigated the discharge characteristics of air gap between the tip of needle-shaped electrode and the soil surface as a parameter of moisture content in soils when the positive and negative 1.2/50㎲ lightning impulse voltages are applied. The breakdown voltage and the discharge light were observed. As a result, the attachment processes of lightning leader to ground are strongly dependent on the grain size and the moisture content of soils. The time to breakdown was shortened with increasing the magnitude of incident impulse voltages. The delay time from application of the highest voltage to breakdown in sand is shortened with increasing the moisture content. The delay time from application of the voltage to breakdown in gravel varied from about 0.5㎲ to several ㎲. As the moisture content in soil increases, the breakdown voltages are decreased and the breakdown voltage versus time to breakdown curves are shifted toward the lower side. The results obtained in this work are similar to those for non-uniform air gap stressed by lightning impulse voltages.