• Journal of the Korean Solar Energy Society
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• v.26 no.3
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• pp.53-62
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• 2006

Since the direct normal radiation and clear day are a main factor for designing any solar thermal and photovoltaic concentrating system, it is necessary to evaluate its characteristics all over the country. The work presented here are the investigation of direct normal radiation and clear day in Korea. The data utilized in the investigation consist of direct normal radiation collected for 14 years('90. 12${\sim}$2004. 12) and clear-day collected for 23 years($1982{\sim}2004$) at measuring stations across the country. The analysis shows that the annual-average daily direct normal radiation is 5.4 kWh/m2 and the annual-average total clear-day is 92.7 days in Korea. We also constructed the contour map of direct normal radiation and clear-day in Korea by interpolating actually measured data across the country.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.142-147
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• 2008

Limited fossil fuels and unstable energy supply are considered as one of the critical problems in architecture requiring large amounts of energy. In order to this challenge, environment-friendly architecture design is required. Especially, Application of solar energy as a clean energy source and one kind of renewable energy. Many sites however are mainly concentrated in the developed countries, and are scarcer within the developing world. Simple radiation estimation models using meteorologically observed input parameters are often used in the applications requiring rough estimations of solar radiation. In this paper, measurements of global solar radiation and cloud data hours in climatological locations in South Korea are used to develop an estimation in solar radiation. The results of measured data are compared with the results obtained from equations, internationally accepted correlations.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.403-404
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• 2010

태양전지는 일사량 및 온도에 의해 출력 특성이 변화하여 최대전력을 얻을 수 있는 위치도 변화한다. 따라서 태양전지의 동작점을 최대 전력점에서 동작하게 하는 최대전력점 추적(MPPT, Maximum Power Point Tracking) 이 필요하다. 본 논문에서는 P&O 방식처럼 자려진동을 하지 않고 최대 동작점에서 머물면서 동작하는 NOC(Non-Oscillation Control) 방법을 제안한다. 이 방식은 빠르게 최대 동작점을 찾을 수 있고 특히 급격한 일사량 변동에 대해 유리한 장점을 갖는다. 최종적으로 제안된 제어기법의 타당성을 검증하기 위하여 3KW급으로 수행된 MPPT 모의 실험을 제시한다.

• Journal of the Korean Solar Energy Society
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• v.29 no.3
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• pp.59-65
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• 2009

In this paper, to find effective way of the production of the distilled water with solar radiation, 4 different boxes of condensation systems were compared. The bottom size of boxes are identical but the angles of top collecting plates are different. During the solar radiation, condensation did not occur and the condensation start when solar radiation was decreased. The maximum condensation reached when the temperatures of the top and bottom parts are equal. The condensation was continued until sunrise with gradually reduced amount. When top plate angle was $45^{\circ}$, condensation was highest compared with the other angles.

• Journal of Internet of Things and Convergence
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• v.8 no.3
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• pp.55-61
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• 2022

In order to reduce greenhouse gases, the main culprit of global warming, the United Nations signed the Climate Change Convention in 1992. Korea is also pursuing a policy to expand the supply of renewable energy to reduce greenhouse gas emissions. The expansion of renewable energy development using solar power led to the expansion of wind power and solar power generation. The expansion of renewable energy development, which is greatly affected by weather conditions, is creating difficulties in managing the supply and demand of the power system. To solve this problem, the power brokerage market was introduced. Therefore, in order to participate in the power brokerage market, it is necessary to predict the amount of power generation. In this paper, the prediction system was used to analyze the Yonchuk solar power plant. As a result of applying solar insolation from on-site (Model 1) and the Korea Meteorological Administration (Model 2), it was confirmed that accuracy of Model 2 was 3% higher. As a result of comparative analysis of the DNN and RNN models, it was confirmed that the prediction accuracy of the DNN model improved by 1.72%.

• Solar Energy
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• v.16 no.2
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• pp.49-63
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• 1996

Site elavation is one of the major factors which is influencing the incoming insolation. Because nonpermanent gases like ozone, water vapor are unmixed components of the atmosphere and their concentrations are function of height, the site elevation effects the relative proportion of the atmospheric constituents. We have measured solar radiation on Sobaek(1,350m) and in Poonggi area(280m). These values were compared to investigate the their charateristics and the potential for the solar utilization as an alternative energy for both high altitude area and low altitude area. From the results, we conclude that 1) Yearly mean 4,093 $kcal/m^2$. day of the horizontal global radiation in Mt. Sobaek was evaluated for clear day. 2) Insolation on Mt. Sobaek is $6{\sim}7%$ higher than Poonggi area during summer and winter seasons. 3) A significant difference of atomospheric clearness index is observed between Mt. Sobaek and Poonggi area at the same latitude.

• The Korean Journal of Applied Statistics
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• v.36 no.1
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• pp.49-62
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• 2023

Solar energy, which is rapidly increasing in proportion, is being continuously developed and invested. As the installation of new and renewable energy policy green new deal and home solar panels increases, the supply of solar energy in Korea is gradually expanding, and research on accurate demand prediction of power generation is actively underway. In addition, the importance of solar radiation prediction was identified in that solar radiation prediction is acting as a factor that most influences power generation demand prediction. In addition, this study can confirm the biggest difference in that it attempted to predict solar radiation using medium-term forecast weather data not used in previous studies. In this paper, we combined the multi-linear regression model, KNN, random fores, and SVR model and the clustering technique, K-means, to predict solar radiation by hour, by calculating the probability density function for each cluster. Before using medium-term forecast data, mean absolute error (MAE) and root mean squared error (RMSE) were used as indicators to compare model prediction results. The data were converted into daily data according to the medium-term forecast data format from March 1, 2017 to February 28, 2022. As a result of comparing the predictive performance of the model, the method showed the best performance by predicting daily solar radiation with random forest, classifying dates with similar climate factors, and calculating the probability density function of solar radiation by cluster. In addition, when the prediction results were checked after fitting the model to the medium-term forecast data using this methodology, it was confirmed that the prediction error increased by date. This seems to be due to a prediction error in the mid-term forecast weather data. In future studies, among the weather factors that can be used in the mid-term forecast data, studies that add exogenous variables such as precipitation or apply time series clustering techniques should be conducted.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.180-181
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• 2010

현대중공업은 2009년 충북 음성에 500kW급 태양광 발전소를 건설하여 태양광 인버터 개발품에 대한 실증시험을 진행하고 있다. 본 연구의 목적은 태양광 발전소내에서의 실제 발전 전력을 분석하여 고품질의 전력을 발전하는 제품을 만들고자 하는 데 있다. 전력의 품질은 태양광 인버터의 제어특성 뿐만 아니라 일사량이나, 구름의 움직임, 온도 그리고, 계통의 부하에 따라 변화하므로 발전량 전영역에서 고품질의 전력을 생산하는 것이 매우 어렵다. 본 연구에서는 전력의 품질을 확인하기 위하여 역률 및 고조파를 측정하여 나타내었다. 연구 결과 저전력에서의 역률 및 고조파의 큰 변화를 확인할 수 있다.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.186-187
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• 2010

현재 국내 기준 약 40만대의 승강기가 운행중이며, 승강기 전력의 약 40%가 회생되고 있다. 본 논문에서는 승강기의 회생전력을 계통연계형 태양광 연계형 인버터에 추가 함으로써 일사량에의존한 태양광 발전의 효율을 개선하고자한다. 제안된 시스템의 동작모드는 크게 연계형 태양광 인버터 발전 및 승강기 회생 전력 부분으로 나누어지며 인터페이스 장치에의하여 승강기 회생 전력을 태양광 발전용 전력 변환 장치로 전송한다. 본 연구에서는 제안한 시스템의 유용성을 확인하기위하여 시뮬레이션 및 실험을 수행하였다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.213-215
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• 2019

태양광 어레이는 일사량과 온도에 의해 출력 특성이 변화하여 전역 최대 전력 점 추종 기법(GMPPT, Global Maximum Power Point Tracking)을 필요로 한다. 기존의 P&O, IncCond 등의 알고리즘은 음영이 발생한 태양광 어레이에서 전역 최대 전력 점을 추종하지 못한다. 본 논문에서는 태양광 어레이의 전압, 전류와 전력의 상관관계를 이용하여 전역 최대 전력점을 추종하는 기법을 제안한다. 제안된 제어기법은 3kW 태양광 인버터 시스템을 구성하여 시뮬레이션을 통해 타당성을 검증하였다.