• 한국산학기술학회논문지
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• 제20권10호
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• pp.229-235
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• 2019

지구 환경문제와 자원 고갈에 따른 에너지 위기로 인해 화석 연료를 사용하지 않아 이산화탄소와 같은 온실가스 배출이 없는 청정 에너지원으로서 신재생 에너지는 중요성이 강조되고 있다. 부유식 태양광발전은 기존의 태양광 발전기술과 플로팅 기술을 융합한 신개념의 발전 방식이다. 종래의 육상이나, 건축물이 아닌 유휴수면에 설치하는 재생에너지원으로 구조체, 계류장치, 태양광 발전설비, 수중케이블 등으로 구성된다. 또한 단위모듈 형태로 설계되어 발전용량에 따라 단위모듈을 서로 연결하여 대규모 발전 시설을 조성할 수 있다. 태양광 발전기는 옥외에 설치되기 때문에 구조물에 대한 풍하중의 영향이 매우 크다. 본 연구에서는 부유식 태양광 발전 구조물에 큰 영향을 주는 풍하중을 전산유체역학을 통해 해석하였다. 유동 특성과 풍하중에 대한 풍향과 경사각의 영향을 분석하였다. 모듈의 개수와 바람의 방향에 따라 최대 하중을 받는 위치와 크기 그리고 태양광 패널과 부유체 주위의 유동 특성을 구하였다. 태양광 패널의 지면에 대한 경사각이 클수록 풍하중은 증가하였다.

• 지적과 국토정보
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• 제49권1호
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• pp.17-27
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• 2019

본 연구에서는 LiDAR 측량을 활용하여 취득한 정밀 지형자료와 센서 기반의 기상데이터 관측시스템을 구축하여 태양광 발전량을 예측하는 연구를 수행하였다. 2018년 평균 일조시간은 4.53 시간으로 나타났으며, 태양광 발전량은 2,305 MWh으로 분석되었다. 그리고 태양광 모듈의 설치각도에 따른 태양광 발전량의 영향을 분석하고자 모듈 설치각도를 $10^{\circ}$ 간격으로 배치한 결과, 모듈 배치 각도 $30^{\circ}$에서 발전시간은 4.24 시간으로 나타났으며, 일 발전량과 월 발전량이 각각 3.37 MWh와 102.47 MWh로 가장 높게 평가되었다. 따라서 모듈 배치 각도를 $30^{\circ}$로 설계시 모듈 각도 $50^{\circ}$에 비해 발전효율이 약 4.8% 상승하는 것을 알 수 있었다. 또한 태양광 모듈의 설치각도에 따른 계절별 태양광 발전량의 영향을 분석한 결과, 날씨가 차가운 11월~2월까지는 모듈 각도가 큰 $40^{\circ}{\sim}50^{\circ}$가 태양광 발전량이 높게 나타났으며 날씨가 따뜻한 3월~10월까지는 모듈 각도가 작은 $10^{\circ}{\sim}30^{\circ}$가 태양광 발전량이 높게 나타남을 알 수 있었다.

• 한국기후변화학회지
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• 제8권1호
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• pp.21-30
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• 2017

Recently, There has been much discussed about unused space. This space can be used in a variety of ways. Utilizing it as a facility, craft shop, and utilizing renewable energy generation facilities. Especially, in terms of climate change should be supplied renewable energy. Renewable energy needs to be developed in terms of responding to climate change, and the recent Paris agreement is also emphasizing the importance of renewable energy. In particular, renewable energy needs to be widely disseminated. And renewable energy is limited space. In this regard, idle land can provide opportunities for securing new renewable energy generation facilities. The introduction of new and renewable energy facilities in idle space can enhance the self-sufficiency rate of the local community, which is significant in terms of responding to climate. In this study, to investigate the possibility of utilizing a unused space for a photovoltaic power generation facility, we investigated the amount of electricity which could be generated through photovoltaic power generation, and the economic effects, using a RETScreen model. The results showed that 9,738 MWh of power can be generated and that $4,540tCO_2eqcan$ be saved. Regarding the economic effect, the net present value of the facility was shown to be 2,247,389,020 KRW. As the net present value was shown to be positive, we believe that the installation of a photovoltaic power generation facility in an unused space would have a positive economic effect. We found the net present value following the fluctuation of the SMP price to be positive, though there was some variation. However, as the economic efficiency was shown to be low because the net present value in relation to the maintenance costs was negative, we believe that maintenance costs must be taken fully into account when evaluating economic efficiency. In particular, as subsidies can be used to cover maintenance costs which must be factored into photovoltaic power generation, we believe that photovoltaic power generation can have an economic effect. Because spaces not currently in use can have a positive economic effect as renewable energy power generation facilities, and can also contribute to the reduction of greenhouse gas emissions, unused spaces are thought to greatly help local governments to cope with climate change as well as reinforcing their related capabilities. We believe our study will help local governments with decisions relating to unused real estate utilization in the future.

• Transactions on Electrical and Electronic Materials
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• 제17권2호
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• pp.57-68
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• 2016

In this study, we present the modern hybrid system based power generation for electric vehicle applications. We describe the hybrid structure of modified current source based DC - DC converters used to extract the maximum power from Photovoltaic (PV) and Fuel Cell system. Due to reduced dc-link capacitor requirement and higher reliability, the current source inverters (CSI) better compared to the voltage source based inverter. The novel control strategy includes Distributed Maximum Power Point Tracking (DMPPT) for photovoltaic (PV) and fuel cell power generation system. The proposed DC - DC converters have been analyzed in both buck and boost mode of operation under duty cycle 0.5>d, 0.5<d<1 and 0.5<d for capable electric vehicle applications. The proposed topology benefits include one common DC-AC inverter that interposes the generated power to supply the charge for the sharing of load in a system of hybrid supply with photovoltaic panels and fuel cell PEM. An improved control of Direct Torque and Flux Control (DTFC) based induction motor fed by current source converters for electric vehicle.In order to achieve better performance in terms of speed, power and miles per gallon for the expert, to accepting high regenerative braking current as well as persistent high dynamics driving performance is required. A simulation model for the hybrid power generation system based electric vehicle has been developed by using MATLAB/Simulink. The Direct Torque and Flux Control (DTFC) is planned using Xilinx ISE software tool in addition to a Modelsim 6.3 software tool that is used for simulation purposes. The FPGA based pulse generation is used to control the induction motor for electric vehicle applications. FPGA has been implemented, in order to verify the minimal error between the simulation results of MATLAB/Simulink and experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.247-251
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• 2003

The developments of the hybrid energy are necessary since the future alternative energies that have no pollution and no limitation are restricted. Currently power generation system of MW scale has been developed. However, even photovoltaic system cannot always generate stable output with ever-changing weather condition. In this paper, sub power generator for hybrid system(photovoltaic 500[W], wind power generation 400[W]) was suggested. Sub power Generator that uses elastic energy of spiral spring to photovoltaic system was also added for the present system. In an experiment, when output of photovoltaic system gets lower than 24[V] (charging voltage), power was continuously supplied to load through the inverter by charging energy obtained from generating rotary energy of spiral spring operates In DC generator. Also, control algorithm of sub power generator is used genetic algorithm(GA).

• 한국태양에너지학회 논문집
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• 제31권1호
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• pp.8-14
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• 2011

Recently, a number of large-scale photovoltaic(PV) power generation system has been installed all over the world. Thus, in order to improve the system efficiency, the optimal design of the large-scale PV systems has become an important issue. DC cable loss of PV array is one of the design factors related to the system efficiency. This paper introduces the array design method of a 500kW Photovoltaic power plant. Three types of the PV array are suggested. Also, string cables, sub-array cables and array cables are designed within 1% of voltage drop in the line, and the DC cable losses are analyzed. The results of this paper show that the DC cable loss of large-scale PV array can be reduced by adopting a proper sub-array design method.

• 한국정보시스템학회지:정보시스템연구
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• 제28권1호
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• pp.115-132
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• 2019

Purpose The purpose of this study is to explain the agrophotovolatic system built by the Korea South-East Power Company and to propose methods to activate the agrophotovolatic system for the development of the renewable energy industry. Design/methodology/approach We conducted a three-step simulation in order to design a photovoltaic module, and we built the agrophotovolatic system based on the results of the simulation. Then, we analyzed the monthly generation of power and the rice harvests produced on farmland using the photovoltaic module. Based on the results of the analysis, we proposed institutional improvements to increase the use of the agrophotovolatic system, and we proposed new business models to increase the participation of farmers and business persons. Findings When we compared the agrophotovolastic system with the general photovoltaic system, we found that the agrophotovoltaic system had higher utilization rates and power generation. An analysis of rice produced on farmland using the photovoltaic module showed that more than 80% of the rice produced on general farmland was harvested. We suggested activation plans that involved the revision of the farmland law and the introduction of renewable energy certificate (REC). We also proposed a land lease model and a farmer participation model as two new business models, and we conducted economic evaluations and sensitivity analyses for both models.

• 제어로봇시스템학회논문지
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• 제8권12호
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• pp.1031-1035
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• 2002

The development of the solar and the wind power energy is necessary since the future alternative energies should have no pollution and no limitation. currently power generation system of MW scale has been developed, but it still has a few faults that its operation depends on with the weather condition. In order to solve these existing problems. combined generation system of photovoltaic(400W) and wind power generation system(400W) was suggested. It combines wind power and solar energy to have the supporting effect from each other. However. since the combined generation system cannot always generate stable output with ever-changing weather condition, power compensation device that uses elastic energy of spiral spring was added. In an experiment. when output of system gets lower than 12V(charging voltage), additional power was from the stored rotational energy of spiral spring.

• 한국태양광발전학회지
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• 제4권2호
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• pp.45-53
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• 2018

Natural gas demand for power generation continued to increase until 2013 due to the expansion of large-scale LNG power plants after the black-out of 2011. However, natural gas demand for power generation has decreased sharply due to the increase of nuclear power and coal power generation. But demand for power generation has increased again as energy policies have changed, such as reducing nuclear power and coal power plants, and abnormal high temperatures and cold waves have occurred. If the gas pipeline pressure can be properly maintained by predicting these fluctuations, it can contribute to enhancement of operation efficiency by minimizing the operation time of facilities required for production and supply. In this study, we have developed a regression model with daily power demand and base power generation capacity as explanatory variables considering characteristics by day of week. The model was constructed using data from January 2013 to December 2016, and it was confirmed that the error rate was 4.12% and the error rate in the 90th percentile was below 8.85%.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1386-1396
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• 2017

In this paper, a new approach is proposed to select the optimal sitting and sizing of distributed solar photovoltaic generation (SPVG) in a radial electrical distribution systems (EDS) considering load/generation uncertainties. Here, distributed generations (DGs) allocation problem is modeled as optimization problem with network loss based objective function under various equality and inequality constrains in an uncertain environment. A boundary power flow is utilized to address the uncertainties in load/generation forecasts. This approach facilitates the consideration of random uncertainties in forecast having no statistical history. Uncertain solar irradiance is modeled by beta distribution function (BDF). The resulted optimization problem is solved by a new Dynamic Harmony Search Algorithm (DHSA). Dynamic band width (DBW) based DHSA is proposed to enhance the search space and dynamically adjust the exploitation near the optimal solution. Proposed approach is demonstrated for two standard IEEE radial distribution systems under different scenarios.