• Journal of the Korean Solar Energy Society
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• v.35 no.3
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• pp.1-8
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• 2015

The MERRA reanalysis data provided online by NASA was applied to predict the monthly energy productions of Donghai Bridge Offshore wind farms in China. WindPRO and WindSim that are commercial software for wind farm design and energy prediction were used. For topography and roughness map, the contour line data from SRTM combined with roughness information were made and used. Predictions were made for 11 months from July, 2010 to May, 2011, and the results were compared with the actual electricity energy production presented in the CDM(Clean Development Mechanism)monitoring report of the wind farm. The results from the prediction programs were close to the actual electricity energy productions and the errors were within 4%.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.125-130
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• 2014

This paper is research result for a development of solar cell silicon ingot glowing(SCSIG) PWM converter system for 120[kW] 3[kA]. The system include 3-phase AC-DC rectifier diode converter of input voltage AC 460[V] and 60[Hz], DC-AC single phase full bridge PWM inverter of high frequency, AC-DC single-phase full wave rectifier using center-tapped of transformer for low voltage 50[V] and large current 3,000[A], carbon resistor load 0.2 [$m{\Omega}$]. PWM switching frequency for IGBT inverter control set 15KHz. The suggested researching contents are designed data sheets of power converter system, PSIM simulation, operating characteristics and analysis results of developed SCSIG system.

• Solar Energy
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• v.4 no.2
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• pp.3-12
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• 1984

In this paper, how to design the wind power generation system is presented. It is shown that the wind system optimization can be achieved by consideration of the four factors; wind statistics, efficiency of conversion of wind energy to electrical energy, average annual energy extracted and load factor. The wind is characterized by a weibull probability function. The Weibull parameter is calculated for the characterizing wind and the primary design specification of ten different sites. Some graphs are presented, which can be used to design a wind system for maximum output of a specified load factor at given site. Two different systems, $V_c=0.4V_R$ and $V_c=0.5V_R$ are discussed, as samples, for investigation of the effects on the system through the variation of cut-in speed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.563-569
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• 2021

With the launch of Compact Advanced Satellite 500 series of various characteristics and the operation of KOMPSAT-3/3A, uses of high-resolution satellite images have been continuously increased. Especially, in order to provide satellite images in the form of ARD (Analysis Ready Data), various pre-processing such as geometric correction and radiometric correction have been developed. For pre-processing of high spatial satellite imagery, auxiliary information, such as solar zenith, solar azimuth and offnadir angle, should be required. However, most of the high-resolution satellite images provide the solar zenith and nadir angle for the entire image as a single variable. In this paper, the solar zenith and offnadir angle corresponding to each pixel of the image were calculated using RFM (Rational Function Model) and auxiliary information of the image, and the quality of extracted information were evaluated. In particular, for the utilization of pixel-based solar zenith and offnadir angle, pixel-based auxiliary data were applied in calculating the top of atmospheric reflectance, and comparative evaluation with a single constant-based top of atmospheric reflectance was performed. In the experiments using various satellite imagery, the pixel-based solar zenith and offnadir angle information showed a similar tendency to the auxiliary information of satellite sensor, and it was confirmed that the distortion was reduced in the calculated reflectance in the top of atmospheric reflectance.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.87.1-87.1
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• 2011

Since early 90's, the solar X-ray telescopes such as Yohkoh SXT and Hinode XRT have observed coronal magnetic structures on the Sun's surface in the range of about $40'{\times}40'$ field-of-view (FOV) covering the full solar disk. Thus it has been stressed by the scientists that the optical structure of solar telescopes should be designed with care for improving the uniformity over a wide FOV. There would be, however, no unique solution in designing the optical system of a telescope for overcoming perfectly the problem of off-axis response variation. As a consequence, the correction of optical imperfectness of telescopes has become an important calibration step that should be performed beforehand when the observed images are to be used for photometric purposes. In particular, a special care should be taken when performing the temperature analysis with thin and thick filters for flaring activities observed at the periphery of the full FOV. From the analyses of both pre-launch calibration and in-flight observation data, the optical characteristics for describing the performance of solar X-ray telescopes, especially in view of their energy dependence, will be introduced and discussed in our presentation.

• Korean Journal of Materials Research
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• v.28 no.11
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• pp.680-684
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• 2018

We investigate the effect of light intensity and wavelength of a solar cell device using photoconductive atomic force microscopy(PC-AFM). A $POCl_3$ diffusion doping process is used to produce a p-n junction solar cell device based on a polySi wafer, and the electrical properties of prepared solar cells are measured using a solar cell simulator system. The measured open circuit voltage($V_{oc}$) is 0.59 V and the short circuit current($I_{sc}$) is 48.5 mA. Moreover, the values of the fill factors and efficiencies of the devices are 0.7 and approximately 13.6 %, respectively. In addition, PC-AFM, a recent notable method for nano-scale characterization of photovoltaic elements, is used for direct measurements of photoelectric characteristics in limited areas instead of large areas. The effects of changes in the intensity and wavelength of light shining on the element on the photoelectric characteristics are observed. Results obtained through PC-AFM are compared with the electric/optical characteristics data obtained through a solar simulator. The voltage($V_{PC-AFM}$) at which the current is 0 A in the I-V characteristic curves increases sharply up to $18W/m^2$, peaking and slowly falling as light intensity increases. Here, $V_{PC-AFM}$ at $18W/m^2$ is 0.29 V, which corresponds to 59 % of the average $V_{oc}$ value, as measured with the solar simulator. Furthermore, while the light wavelength increases from 300 nm to 1,100 nm, the external quantum efficiency(EQE) and results from PC-AFM show similar trends at the macro scale but reveal different results in several sections, indicating the need for detailed analysis and improvement in the future.

• Journal of the Korean Solar Energy Society
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• v.26 no.4
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• pp.25-30
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• 2006

10kW wind turbine has been successfully commissioned at the King Sejong station in April, 2006. The wind turbine installed is a part of the R&D program for developing a solid wind/diesel hybrid power control system for a remote area such as Antarctica. At the same time, the current research aims to develop an anti-icing and de-icing technologies for a small wind turbine rated under 50kW. Since its commissioning, the turbine has generated about 500kWh for 47days without any system faults. Although sufficient data have not been obtained yet, any trouble has not occurred in the wind/diesel hybrid system based on the current analysis. Concerning on the environmental impact by the wind turbine operation, the turbine is installed within the station boundary in order to meet the Madrid protocol. Therefore, wind turbine operation meets the international requirements for preservation of antarctic ecosystem.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.306-309
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• 2008

Renewable energy information becomes one of the greatest issues, but it is difficult for a general user to manage and utilize new renewable energy information. Therefore we develop the utilization system of the resource map which aimed to provide the information for space analysis and vertification of the validity for development of each part of solar, wind, smallhydro, biomass, geothermal. But this system is needed to gather more supporting data and make resonable index to make various decisions.

• Solar Energy
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• v.8 no.2
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• pp.26-38
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• 1988

If proper design and selection of the working fluid are made the power generation system of temperature difference could achieve more efficient results than others. This paper is to analysis the production of its power generation due to several parameters. Making the power generation system, the characteristics of power output are investigated to obtain its basic data for design. This results of this experiment are as follows. 1. The most proper working fluid in the system is Freon-22 having high stability and difference between the outlet pressure, $P_E$ of evaporator and outlet pressure, $P_c$ of Condenser. 2. With the increase of temperature difference between evaporator and condenser, the output in the system increases linearly. 3. The generation efficiency is largely dependent on the type or form of propeller, nozzle and optimum design of heat exchanger.

• Current Photovoltaic Research
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• v.6 no.3
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• pp.69-73
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• 2018

PV system is consisted with PV module, inverter and BOS(balance of system). To have robustic operation more than 20 years, the expected and guaranteed durability and reliability of products should be met. Almost components of PV system are qualified through IEC standards at test laboratory. But the qualification certificate of product does not ensure long-term nondefective operation. PV module's expected life time is nowadays more than 20 years and annual maximum power degradation ratio would be less than -1%. But the power degradation ratio is basically based on real data more than several years' record. Developing test method for ensuring annual maximum power degradation ratio is very need because there are many new products every month with new materials. In this paper, we have suggested new test method under continuous artificial light irradiation test condition for analyze expected maximum power drop ratio.