• 전기학회논문지
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• 제67권11호
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• pp.1401-1407
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• 2018

This paper proposed a method of energy storage system (ESS) operation to increase acceptable production of renewable energy (RE). We analyzed the rebound effect that does not show a demand increase even if the capacity of the ESS is increased and considered the charging time by analyzing the time when the output limit is most generated. The rebound effect was mitigated by adjusting the discharging time of the ESS, and the effect of the increase of acceptable production of the renewable energy was analyzed by adjusting the charging time.

• 조명전기설비학회논문지
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• 제24권4호
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• pp.43-49
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• 2010

콘덴서는 유도성 부하의 늦은 역률 보상으로도 사용되며, 비선형 부하에서 발생하는 고조파를 저감하기 위해 리액터에 직렬로 연결하여 사용되기도 한다. 전압, 전류의 증가와 열의 발생은 콘덴서 수명에 많은 영향을 준다. 전압이 증가할 경우 전류가 증가하고, 주파수의 증가도 전류의 증가로 이어지기 때문에 전압과 주파수의 증가는 바로 열의 증가로 콘덴서 절연에 스트레스로 작용하여 고장의 원인을 제공할 수 있다. 본 연구에서는 전압의 크기와 주파수를 변화시킬 경우 콘덴서에서 발생하는 열의 분포도를 열화상 카메라로 측정하였다. 측정결과 전압과 주파수의 증가는 높은 열을 발생시켜 콘덴서의 수명을 단축시키는 요소로 작용함을 확인할 수 있었다.

• 한국농공학회논문집
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• 제56권4호
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• pp.29-39
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• 2014

In this study, we performed a non-stationary frequency analysis using a power model and the model was applied for Seoul, Daegu, Daejeon, Mokpo sites in Korea to estimate the probable precipitation amount at the target years (2020, 2050, 2080). We used the annual maximum precipitation of 24 hours duration of precipitation using data from 1973 to 2009. We compared results to that of non-stationary analyses using the linear and logistic regression. The probable precipitation amounts using linear regression showed very large increase in the long term projection, while the logistic regression resulted in similar amounts for different target years because the logistic function converges before 2020. But the probable precipitation amount for the target years using a power model showed reasonable results suggesting that power model be able to reflect the increase of hydrologic extremes reasonably well.

• Journal of Power Electronics
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• 제7권4호
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• pp.286-293
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• 2007

This paper proposes a distribution voltage control method when a voltage increase condition occurs due to reverse power flow from the clustered photovoltaic (PV) system. This proposed distribution voltage control is performed a by distribution-unified power flow controller (D-UPFC). D-UPFC consists of a hi-directional ac-ac converter and transformer. It does not use any energy storage component or rectifier circuit, but it directly converts ac to ac. The distribution model and D-UPFC voltage control using the ATP-EMTP program were simulated and the results show the voltage increase control in the distribution system.

• 전기학회논문지P
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• 제52권1호
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• pp.28-34
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• 2003

In this paper, a predistortion linearizer using series diode is proposed for linearizing the power amplifier in microwave radio systems. The power amplifier should be operated near saturation region to achieve high efficiency. But at this region, amplitude and phase distortions of the amplifier remarkably increase with the increase of input power and cause a significant adjacent channel interference. The linearizer is composed of a series diode with a parallel capacitor, which provides positive amplitude and negative phase deviations with the increasing input power. This type of linearizer using the nonlinearity of diode has improved the C/I(Carrier to Intermodulation Distortion) ratio well. By applying this linearizer to two-tone 880MHz power amplifier, adjacent channel leakage power is improved up to 5dBm.

• 전기의세계
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• 제19권4호
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• pp.18-23
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• 1970

A neutron detector, in general, can not be utilized as the thermal neutron detecting chamber in the nuclear power reactor, especially P.W.R. due to the characteristics of high temperature, high pressure and high neutron flux in a reactor vessel. We have performed an experiment to detect the thermal neutrons at 400.deg. C and high flux of thermal neutron in a power reactor. Coating boron-10 on the aluminium plates by means of surface diffusion method at 600.deg. C for 5 hours in an electric furace, also we made a typical chamber which was compensated ionization chamber filled with free air as an ionization gas. It was checked the chamber characteristics in the TRIGA MARK-II Reactor at the power level from zero to 250KW. The chamber current showed a perfect linear increase to power increase. However, many variation of the measured current were observed within the power of 50KW.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.25-26
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• 2014

Renewable energy sources such as wind and solar power are free and can be easily harvested everywhere. However, one of the biggest problems when using this kind of energy source is how to increase the efficiency of power conversion system. This paper introduces a modified 3-phase inverter in order to increase the power conversion efficiency. By adding 3 bi-directional switches at output of the inverter, the current flow back DC source during zero state is prevented to minimize leakage current, so that the efficiency of whole system is increased. The proposed topology also improves the power quality to satisfy the total harmonics distortion (THD) requirement. In order to verify the effectiveness of the proposed topology, simulation results are carried out using Simulink in MATLAB.

• 전자공학회논문지C
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• 제35C권2호
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• pp.36-47
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• 1998

Low power circuit techniques have been developed to realize the highest possible performance of embedded SRAM at 1V power supply with$0.5\mu\textrm{m}$ single threshold CMOS technology in which the unbalance between NMOS and PMOS threshold voltages is utilized to optimize the low power CMOS IC design. To achieve the best trade-off between the transistor drivability and the subthreshold current increase, the ground potential of memory array is raised to suppressthe subthreshold current. The problems of lower cellstability and bit-line dealy increase due to the enhanced array ground potential are evaluated to be controlled within the allowable range by careful circuit design. 160MHz, 128kb embedded SRAM with 3.4ns access time is demonstrated with the power consumption of 14.8mW in active $21.4{mu}W$ in standby mode at 1V power supply.

• 한국세라믹학회지
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• 제54권1호
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• pp.38-42
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• 2017

Vanadium nitride (VN) coatings were deposited using inductively coupled plasma (ICP) assisted sputtering at different ICP powers. Microstructural, crystallographic and mechanical characterizations were performed by FE-SEM, AFM, XRD and nanoindentation. The results show that ICP has significant effects on coating's microstructure, structural and mechanical properties of VN coatings. With an increase in ICP power, coating microstructure evolved from a porous columnar structure to a highly dense one. Single- phase cubic (FCC) VN coatings with different preferential orientations and residual stresses were obtained as a function of ICP power. Average crystal grain sizes of single phase cubic (FCC) VN coatings were decreased from 10.1 nm to 4.0 nm with an increase in ICP power. The maximum hardness of 28.2 GPa was obtained for the coatings deposited at ICP power of 200 W. The smoothest surface morphology with Ra roughness of 1.7 nm was obtained in the VN coating sputtered at ICP power of 200 W.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.858-863
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• 2007

With increase of load power the case it will not be able to supply the power which is necessary to the vehicle, it establishes dosage increase of main transformer of substation or power compensation equipment, and must supply the power which is necessary. But like this method the expense and the hour when it is considerable are necessary. As an alternative plan, if neighborhood substation can supply power through parallel feeding then it can supply power applying the equipment of existing. So we investigate the possibility of parallel feeding method between neighboring substations through measuring results of voltage phase difference and analysing feeding circuit,