• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.1
• /
• pp.127-136
• /
• 2013

The islanding detection and prevention function in the important performance of the grid-connected inverter is the essential details which should be considered for worker's safety to maintain the system. This paper tries to suggest the active frequency shake islanding detection technique in the grid-connected PV generation system using sunlight. The existing active frequency drift method algorithm is described to suggest active frequency shake method algorithm. And, the algorithm which can reduce the non-detection zone, improve THD, and improve the detection speed in comparison with the existing algorithm is suggested. And we applied the proposed algorithm to the 3kW grid-connected photovoltaic inverter generation and verified the feasibility of the technique through the simulation and experiments.

• Journal of the Korea Concrete Institute
• /
• v.28 no.5
• /
• pp.601-609
• /
• 2016

Recently, extreme climate change has been occurring globally not only in the simple form of temperature increases but also in a wide range of extreme climatic events, such as abnormal drought conditions and frequent typhoons. In addition, climate change is delaying the construction period of concrete structures, increasing related economic losses. Forcing construction projects for completion without considering climate change is leading to concrete quality deterioration, poor quality constructions, and consequent casualties and property damage. Therefore, to address these problems and provide a countermeasure to climate change, the present study selected wind speed, and sunlight exposure time as the most important curing conditions among the climate factors affecting concrete structures and examined their effects on the curing and durability of concrete structures. In addition, for the analysis of the experimental results, this study proposed a process of performance based evaluation (PBE) of concrete strength and durability using a method of Satisfaction Curve (SC) generation.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.16 no.4
• /
• pp.27-40
• /
• 2013

These day morden cities have serious climatic problems due to enviornmental load caused by excessive development of urbanization. As technological improvement to answer to various ecological disasters and climate changes are also called on the field of construction, inter-disciplinary studies linked to the estabilishment of sustainable energy generation systems and enviornmental control is needed in a consilient point of view. This study aims to analyse optimal site conditions for photovoltaic system and green roof planting through solar radiation simulation in a integrated perspective. In so doing, it seeks to proffer basic study for developing a sound use of roof area that is sustainable in environmental and resources aspects. A computer simulation showed that, in the case of total seasonal solar radiation, summer season resulted 312.5kWh in 35% of total annual solar radiation. This season indicated the lowest radiation rate of the year for direct sunlight in 45.8% of total seasonal solar radiation. Due to such solar radiation simulation, at the largest optimal planting area, Glechoma hederacea var. longituba secured $719.16m^2$ of gross roof area.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.3 no.1
• /
• pp.39-45
• /
• 2008

The geographic intelligence service from mobile environment in site to get the information which is necessary from site immediately and it dynamically in order to apply, with the box there is possibility to raise the expense and efficiency of the service object person. Currently geographic intelligence service from mobile environment in order provides a service about the geographic intelligence which is complicated large scale terrain stays emptily in vehicle four information which is simple, includes from the research is necessary about contents provision and control which have become optimum anger to the system evening sunlight technique.

• Journal of Sericultural and Entomological Science
• /
• v.4
• /
• pp.33-39
• /
• 1965

Author investigated the control measure and the life cycle of the mulberry sucker, Anemoneura mori Schwarz. The results are as follows; 1. It is clear that the life cycle of mulberry sucker is one generation a year, but not obvious about the duration of pupa. 2. Even though various insecticides were used for control, they are not of a practical value during the egg stage. It is, however, believed that the mulberry sucker, when become larvae, can be controlled by spraying about 400 litres per 1 tanbo( DDVP, 1000$\times$). 3. Author recommends the control measures which you may use not only an insecticide, but also cut off branches so as to make leaf get enough sunlight and ventilation.

• New & Renewable Energy
• /
• v.4 no.4
• /
• pp.3-9
• /
• 2008

In design PV (photovoltaic) system, there are many important factors to consider for best site selection. It is essential to understand to know the amount of sunlight available and how to minimize the shadings. This study presents basic concepts for understanding sun's position and insolation. also it gives easy tools for topography analysis. Finally, this study shows some theoretical calculations of power generation losses by topographic obstacle's elevations and disadvantages in economic feasibility, that is about 7million won loss per year for case of 10 degree topography elevation with assuming average Korea's topography elevation as 5 degree.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.87-90
• /
• 2008

In design PV(photovoltaic) system, there are many important factors to consider for best site selection. It is essential to understand to know the amount of sunlight available and how to minimize the shadings. This study presents basic concepts for understanding sun's position and insolation. also gives easy tools for topography analysis. Finally, this study shows some theoretical calculations of power generation losses and disadvantages in economic feasibility.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.316-318
• /
• 1994

Photovoltaic is considered to be one of the most promising technologies which can greatly contribute to future energy supply because or a large, secure, essentially inexhaustible and broadly available resource -sunlight. This paper analyzes reduction of synthetic power peak value through weather data and quantity or generation. This explanation and estimations analyses grid connected power system.

• Design & Manufacturing
• /
• v.16 no.2
• /
• pp.20-25
• /
• 2022

In line with the rapid economic growth of many countries, fossil fuel energy sources are also rapidly depleting. Therefore, the price is also rising rapidly, so it is necessary to develop new and renewable energy sources such as hydropower, geothermal power, nuclear power, wind power and solar energy to replace fossil fuel energy in the future. In this study, development of rotating concentrator module system, development of rotating module control control system, development of lamp and charge control controller, configuration and prototype production of rotating concentrating solar LED street light system, efficiency of rotating concentrating solar LED street light, and power production. The research was conducted in the order of evaluation of comprehensive performance tests such as consumption and consumption. As a result, the developed high-efficiency rotation-concentrating hybrid solar LED street light module system has a 50% higher light-gathering efficiency than existing products by tracing sunlight by self-developing a rotation-collecting module on existing solar LED street lamps according to the characteristics of Korea's topography. and the power generation was improved by more than 40%.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.6_1
• /
• pp.1001-1010
• /
• 2023

To solve the problem that photovoltaic panels can not harvest electrical energy at a cloudy day and night, a floating solar thermoelectric generator (FSTEG, hereafter) is studied. The FSTEG is consisted of a dome shaped Fresnel lens to condense solar energy, a thermoelectric module connected with a heat sink to keep temperature difference, a floating system simulating a wavy ocean and an electrical circuit for energy storage. The dome shaped Fresnel lens was designed to have 29 prisms and its optical performance was evaluated outdoors under natural sunlight. Four thermoelectric modules were electrically connected and its performance was evaluated. The generated energy w as stored in a Li-ion battery by using a DC-DC step-up converter. For the application of ocean environment, the FSTEG was covered by the dome shaped Fresnel lens and sealed to float in a water-filled reservoir. The harvested energy shows a potential and a method that the FSTEG is suitable for the energy generation in the ocean environment.