• Proceedings of the KIEE Conference
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1392-1394
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• 2003

This paper presents the actual test data of 3 phase, 9 pole, 3.6 [kw] synchronized wind-power generator controlled by hinged vane system and the possibilities of the small mount wind-power generations at the south-east coast of Ul-san. It also shows the data of the wind-velocity acquired by wind-direction sensor, calculation and analysis of the estimated electrical generation power, energy storage systems, and the efficient usages of the wind-power system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제18권3호
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• pp.156-162
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• 2004

In this paper, a technique that estimate the optimal capacity of the solar-wind hybrid power system for minimizing the total monthly electric power expenses is presented. The hybrid power system is assumed to be operated in connection with the utility power system and electric bill be paid for the power not covered by the hybrid system generation. Monthly generation cost is estimated based on total life-cycle cost analysis. The monthly utility power bill is assumed to be increased quadratically in proportion with the net utility power consumption which is the difference between the total monthly load minus the hybrid system generations. Test results demonstrate applications potential of the proposed technique.

• The Journal of the Acoustical Society of Korea
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• 제35권3호
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• pp.192-201
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• 2016

Condition Monitoring System (CMS) has been used to detect unexpected faults of wind turbine caused by the abrupt change of circumstances or the aging of its mechanical part. In fact, it is a very hard work to do regular inspection for its maintenance because wind turbine is located on the mountaintop or sea. The purpose of this study is to find out distribution patterns of vibration signals measured from the main mechanical parts of wind turbine according to its operation condition. To this end, acceleration signals of main bearing, gearbox, generator, wind speed, rotational speed, etc were measured through the long period more than 2 years and trend analyses on each signal were conducted as a function of the rotational speed. In addition, correlation analysis among the signals was done to grasp the relation between mechanical parts. As a result, the vibrations were dependent on the rotational speed of main shaft and whether power was generated or not, and their distributions at a specific rotational speed could be approximated to Weibull distribution. It was also investigated that the vibration at main bearing was correlated with vibration at gearbox each other, whereas vibration at generator should be dealt with individually because of generating mechanism. These results can be used for improving performance of CMS that early detects the mechanical abnormality of wind turbine.

• Journal of the Korean Society for Precision Engineering
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• 제29권9호
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• pp.958-963
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• 2012

Characteristics of off-grid hybrid renewable energy sources for high mountain villages are discussed. Considering reliability of electric power generation, Photovoltaic (PV)-wind hybrid and PV-hydro hybrid system are suggested. Connecting two or more villages with these hybrid systems, an extended hybrid off-grid can be formed. Sustainability of entire system is important in design of off-grid system, and income generation of the village people using the electricity should be considered.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제14권2호
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• pp.113-116
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• 1978

To ascertain the feasibility of the energy utilization in the sea adjacent to Korea, the distribution of the vertical temperature difference and the seasonal variation in the southeastern Yellow Sea are studied in relation to the sea water circulation. In summer, a region of high vertical temperature difference of approximately 16$^{\circ}C$ was found at a distance of approximately 40 miles from the western coast of Korea. It is located at the west of 125${\circ}$ 30`E and at the north of 34${\circ}$N. The vertical temperature structure is sustained by the inflow of Yellow Sea Warm Current water, the warming of the surface water of the Yellow Sea and the periodical renewal of the Yellow Sea Cold Water. It may be stated that power can be obtained from the sea water by making the use of the temperature difference. The vertical temperature difference was around 14$^{\circ}C$ in the western and southern waters of Jejudo Island. The vertical temperature difference decreases in autumn, and disappears due chiefly to the vigorous convective vertical mixing in winter when the northwest monsoon prevails. The power can be obtained from sea throughout the year, if power generation by the temperature difference is combined with that by wind and wave, and systemized in such a way that the former is employed in the hot season of summer, while the latter in winter and spring.

• Journal of Advanced Marine Engineering and Technology
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• 제40권4호
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• pp.336-341
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• 2016

This paper presents an implementation of a communication network in wind turbines, which exploits the power-line communication system (PLC). We used an inductive coupling unit and a multi-interface device to connect a data-communication terminal to the power line, to ensure that stable communication was possible at various electric current and voltage values of the generator. The results of the operation tests conducted on an operational wind turbine showed that the implemented PLC demonstrated a transmission rate of at least 43 Mbps with a 100% success rate. Moreover, a real-time image was transmitted. Thus, the system could be a useful alternative for implementing a communication network in wind turbines that does not require additional channels. Since the presented system is easy to implement, and can support various interfaces for data communication, it will be quite useful when a real-time monitoring system is launched in wind turbines.

• Composites Research
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• 제36권1호
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• pp.32-36
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• 2023

Recently, as global environmental issues for sustainable development, such as carbon neutrality, have emerged, disposal methods of glass fiber composites, a material of existing wind turbines, have become a problem. To solve this problem, in this study, 30kW wind turbine blades were manufactured using flax fiber-based composites, which are eco-friendly natural fiber composites that can replace existing glass fiber composites, and their suitability was evaluated. First, mechanical strength tests were conducted to verify the feasibility of using eco-friendly natural flax fiber composites as a wind turbine blade material, and as a result, better strength were confirmed compared to previous studies on the properties of flax fiber composites. In addition, the suitability was confirmed through a static strength performance evaluation test to measure the static strength of the flax fiber composite blade using the manufactured 30kW class flax fiber composite blade.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.139.1-139.1
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• 2010

제 3차 국가에너지기본계획이 시행됨에 따라 전체 에너지 공급량 중 신재생에너지가 차지하는 비율은 점차 늘어날 전망이다. 이와 관련하여 2012년부터 RPS 시행이 확정되었다. RPS(신재생에너지 의무비율할당제)는 신재생에너지에 의한 발전 비율을 설정함으로써 공급을 늘리는 긍정적인 측면이 있으나 이와 동시에 전기요금 인상을 수반한다. 요금 인상으로 인하여 발생할 수 있는 소비자의 반감을 완화시키고 전기요금에 대한 현실적인 합의점을 찾으려면 소비자가 재생에너지 전력에 대하여 어느 정도의 지불의사를 가지고 있는지에 대한 연구가 선행적으로 진행되어야 한다. 한편 RPS의 도입은 신재생에너지 원간 가격경쟁을 촉진시키게 된다. 이 과정에서 성장잠재력이 높은 에너지원이라 하더라도 현재의 발전단가가 높다면 잠재력을 발휘하기 전에 도태될 가능성이 있다. 이러한 RPS 도입의 영향에 대처할 수 있는 정책수립의 기초자료를 마련하기 위해, 재생에너지 전력에 대한 소비자 측면의 효용이 원별로 분석될 필요가 있다. 본 연구에서는 조건부 가치평가법(Contingent Valuation)을 적용하여 수력, 풍력, 태양광으로 발전된 재생에너지 전력에 대한 지불의사액(Willingness to Pay)을 추정하였다. 단일 설문지 내에서 여러 에너지원에 대한 지불의사액을 순차적으로 물어보게 될 경우, 질문순서가 지불의사액 추정에 편의를 가져오는 순서효과(Sequence Effect)가 발생할 수 있다(Boyle et al.,1993). 이러한 순서효과를 제거하기 위해서 유형에 따라 질문순서를 다르게 하여 각 에너지원에 대한 지불의사액을 묻는 방향으로 설문을 설계하였다. 분석결과 수력, 풍력, 태양광으로 발전한 전력에 대한 지불의사액 간에는 유의한 차이 가 나타나지 않았으며, 순서효과로 인한 편의 또한 지불의사액에 유의한 영향을 미치지 않는 것으로 관측되었다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제21권6호
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• pp.129-134
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• 2021

Recently, the demand for electricity is gradually increasing due to the rapid industrial development and the improvement of living standards. In the case of Korea, which is highly dependent on fossil fuels due to such a surge in electricity demand, reduction and freezing of greenhouse gas emissions due to international environmental regulations will immediately lead to a contraction in industrial activities. Accordingly, there are many difficulties in competition with advanced countries that want to link the environment with the country's industrial production activities, and the development of alternative energy as a countermeasure is of great interest around the world. Among these new power generation methods, small-scale power generation facilities with relatively small capacity include photovoltaic generation, wind power generation, and fuel cell generation. Among them, the fuel cell attracts the most attention in consideration of continuous operation, high power generation efficiency, and long-term durability, which are important factors for practical use. Therefore, in this paper, the fuel cell power generation system was researched and constructed by designing the power conversion circuit necessary to finally obtain the AC power used in our daily life by using the DC power generated from the fuel cell as an input.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2011년도 학술발표회
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• pp.216-219
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• 2011

신.재생에너지는 머지않아 고갈될 것이라 예측하고 있는 화석에너지의 대체에너지로서 대형 홍수와 국지적 집중호우, 가뭄과 전염병, 기근 등 우리인류의 생존을 위협하는 재앙을 어느 정도 줄일 수 있고, 온실효과 가스를 저감하고자 하는 하나의 방법으로서 가스배출량이 적은 수력, 풍력, 태양광 등의 재생에너지를 이용한 방법이다. 이 중 물은 무한적인 자원이 아니기 때문에 소중히 여기고 순환과정을 통하여 재활용 될 수 있고, 친환경적이고 장기적인 수명과 다른 자원을 사용하는 발전소들보다 더 효율적이며 복원 가능성이 크고 다른 오염유발 에너지 자원을 대신한다. 본 연구에서는 경상북도 북부지역 5개 지점의 소수력발전 후보지점에 대한 평 갈수기 및 홍수기의 유량측정에서 수위-유량관계곡선식의 유도등의 목적을 달성하기 위하여 2009년 3월부터 2010년 9월까지 5개 지점을 대상으로 현지조사 및 자료수집, 측량작업, 유량측정 등을 실시하였다. 본 유량측정을 통하여 경상북도 북부지역의 최적 소수력 발전지점 선정을 위한 기초자료를 제공할 수 있을 것으로 판단된다.