• 대한전기학회논문지:전력기술부문A
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• 제52권8호
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• pp.437-443
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• 2003

In this paper an expert system is developed to decide the resetting area of protective devices in power transmission systems. A configuration change in power transmission networks from a substation extension such as new line or bus addition need resetting of protective devices around the point of configuration changes. To find the resetting area in complex power system is very difficult, especially when the distance protective relays are considered to be reset. The proposed expert system, in this paper to find the resetting area has many rules based on the changes of fault currents and apparent factors from the power system alteration. It solves the problem to find relay resetting area using the network information in the database and the rule-base. The case study shows a result of the problem to find relay resetting area in KEPCO system when there is any configuration change.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권4호
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• pp.208-216
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• 2005

Recently, the study of islanding phenomenon, maintains its operation even when the utility grid is removed has lead to the trend of utility interactive inverters in photovoltaic generation systems. In this paper, a novel Anti-islanding method is presented. the proposed method can keep the real average power component constant by MPPT control and cause the load current frequency with only change of reactive power component under the islanding condition. its periodical change of Reactive power component can decrease the NDZ(Non-Detective zone) so that the detection of various loads will be possible. the insufficient effect if additional reactive power component to the grid is proved theoretically and the islanding detection is also confirmed from a experimental result with a inverter for 3kW photovoltaic generation system applied the proposed Anti-islanding method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.74-77
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• 2002

Combined generation system of Photovoltaic and wind generation have shortcoming that is different output power according to change of weather. So, the combined generation system is required backup system that such as a storage battery to supply energy, when not enough photovoltaic and wind power source for power supply equally and continually, because the energy source is changeable and stable through change of weather as irradiation, temperature, wind speed, wind direction, seasons, etc..

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(2)
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• pp.433-438
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• 1997

It Is necessary to calculate radwaste effluent due to change in the fuel defect rate to see the overall change in radwaste effluent md, at present, for this type of calculation DAMSAM code is being used. However, often, one can not access easily to this code with many reason and so we have chosen this case, in this paper, to show a very simplified but quite accurated calculation method without the solving equations. The physical meanning of the parameters in the equations used in DAMSAM have been reviewed to simplify the equations and the result calculated with this method have been compared with that of DAMSAM.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.48-50
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• 2005

New environment change of electric power system focused in consumer's energy supply and demand. But electric power reliability preservation and reliability improvement countermeasure also need for long-term. It is need that change equipments that is composing electric power system in well-timed time and by maintaining, prevent breakdown beforehand and prevent consumer's power interruption by equipment fail. However, as only quantitative estimation is available by reliability estimation method that is presented in existing, it is no to use in dictionary fault prevention. Therefore, applied optimum reliability preservation through existent equipment fault data analysis of electric power system in equipment replace side, and this when maintain equipment replace of electric power system for reliability preservation using responsiveness analysis to base ordering evaluate. In existing about main equipment plain that this paper is power system the valued failure rate use this by score and precedence of electric power system equipment for replace of system considered expense.

• 플랜트 저널
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• 제7권4호
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• pp.58-66
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• 2011

The power plant companies reached the culmination for growth in the domestic market. Besides, we have faced many challenges such as an electricity opening market trend for overseas, banning the use of coal due to the United nations framework convention on climate change, and the meticulous attention regarding the government's electricity charge plan. On the other hand, the overseas business has been a critical issue since China and many other developing countries expanded their projects abroad. Another factor is that power plant industry is being privatized, and it made the market regulation a bit loose. Thus, the market environment became favorable toward those companies which planned many overseas businesses. In this research, the power plant company's current condition for construction and operation as well as its technical competitiveness were analyzed, and an alternative plan using SWOT analysis for entering an oversea market was made. It dealt with both internal and external factors. Also, examined was the current situation under the power plant industry dealing with restructure for electric industry, lack of fossil fuel, and the United nations framework convention on climate change. From the research, it was suggested that many successful strategies to enter the overseas business by using the market trend I researched.

• Communications for Statistical Applications and Methods
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• 제16권3호
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• pp.511-518
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• 2009

We consider the problem of testing for change and estimating the unknown change-point in a sequence of time-ordered observations from the binomial and Poisson distributions. Including the likelihood ratio test, Gombay and Horvath (1990) tests are studied and the proposed change-point estimator is derived from their test statistic. A power study of tests and a comparison study of change-point estimators are done via simulation.

• 조명전기설비학회논문지
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• 제19권1호
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• pp.109-116
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• 2005

풍력 및 태양광 발전시스템은 화석에너지의 고갈에 대한 대체에너지로 각광을 받고 있으며, 환경오염을 발생하지 않고 무한정으로 사용할 수 있으나 풍속과 태양광의 변화에 따른 안정성의 문제가 발생한다. 풍력발전시스템의 경우 태풍과 급속한 풍속의 변화에 의해 시스템의 안정성 문제가 발생한다. 본 논문에서는 풍속을 이용한 피드백 제어를 기초로 하는 자동강풍제어기를 포함하는 풍력 발전시스템을 구성하였으며, 이를 다양한 조건의 실험을 통하여 입증하였다. 태양전지 어레이의 최대 출력을 위한 MPPT제어와 고르지 못한 DC 전압을 정류하기 위하여 buck-boost컨버터를 사용하였고, 실험을 동하여 시스템 출력전류 리플 저감의 결과를 확인하였다.

• 한국항행학회논문지
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• 제24권4호
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• pp.291-298
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• 2020

본 연구는 입자 무리 최적화 (PSO; particle swarm optimization) 알고리즘을 이용하여 기존의 MPPT 알고리즘보다 신속하게 MPP를 추적할 수 있는 모델을 제안하였다. 제안 모델은 PSO 알고리즘에서 gbest 및 pbest의 가속 상수를 높게 설정하여 신속하게 MPP 지점을 추적하고 이로 인한 전력 불안정 문제점을 제거하였다. 또한, 일사량의 급격한 변화에 따른 태양광 패널의 전력 변화를 감지하여 알고리즘을 다시 실행하였다. 실험결과, 일사량이 691.5W/m2에 대해서 MPPT 시간이 0.03초와 전력이 131.65로서 기존의 P&O와 INC 알고리즘보다 높은 전력과 빠른 속도로 MPP를 추적하였으며, 일사량 변화에 따라 신속하게 MPP를 추적하였다. 제안 모델은 태양광 패널이 병렬로 연결되어 있는 태양광 발전소에서 부분적인 음영에 의해 전력량의 변화를 감지하였을 경우에도 적용할 수 있다. 본 연구는 MPPT 알고리즘을 개선하기 위해 MFO (moth flame optimization) 및 WOA (whale optimization algorithm)와 같은 최적화 알고리즘에 대한 비교 연구가 필요하다.

• 대한임베디드공학회논문지
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• 제1권1호
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• pp.1-7
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• 2006

In this paper, a novel power management structure for an energy harvesting pervasive system is proposed. The system considers the power state of each subsystem to assign proper power sources. The switch matrix structure utilizes each power source to reduce the peak current of the battery. The power management structure can be interfaced to an embedded system power supply without significant design change.