• KIEAE Journal
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• v.11 no.4
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• pp.29-36
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• 2011

The aim of this study was to study the functions and roles of Green Community Rediscovery Center (GCRC) in terms of community integration, to design GCRC with various types of green roofs, and to investigate the possibility of applying a renewable energy system (e.g., PV) to the building greenery systems. The four major functional modules for GCRC were suggested: implementation of ecopark and community gardens with environmental education programs, implementation of green housing model with education programs, Discover Science Center, and implementation of green business model with education programs. Three major functions of the center are also presented in terms of design: 1) functions of community gardens; 2) establishment of a green business model, community composting system and an urban farming system; and 3) roles of community gardens in social interactions within GCRC. GCRC provides residents with the opportunities of community gardens, urban farming based on a successful recycling system, as well as a green business model and environmental education programs near their homes. The air temperature of the green roof (utilizing Sedum sarmentosum as a cover plant) was approximately $3^{\circ}C$ lower than that of the non-green roof, indicating a potential efficiency increase in PV systems for GCRC. It was concluded that the GCRC suggested would enhance the neighborhood satisfaction, improve the quality of life and contribute to social integration and community regeneration.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.69-72
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• 2009

In this paper, the Stand-alone underground water pumping system was developed that is consist of Submersible Pump (AC type), Photovoltaic Array and Power converter by the application of solar energy. And also wish to introduce system that is possible to supply of drinking water or water for agriculture using solar energy at desertification area or a Off-grid area, interior etc. and operation test results. This system can use in deep tube well of 200m range with common Submersible Pump and maximized to the quantity of pumping through M.P.P.T control. Also system availability raised through apply various driving mode.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.3
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• pp.219-223
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• 2016

DC microgrid system is attracted attention in the world, because DC distribution system is more energy efficient than AC distribution system. To analyse the contribution effects of distributed generation(DG) in LVDC distribution system through modeling the Rectifier, DC/DC converter, Energy Storage System(ESS) and Photovoltaic(PV). using PSCAD/EMTDC. This paper analyses fault response characteristics in LVDC distribution system according to the interconnection and islanding operation of DG. Based on research results on the paper, direction for development of fault current reduction method for LVDC distribution system is suggested.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.18-26
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• 2014

A microgrid can play a significant role for enlargement of renewable energy sources and emission reduction because it is a network of small, distributed electrical power generators operated as a collective unit. In this paper, an application of optimization method to economical operation of a microgrid is studied. The microgrid to be studied here is composed of distributed generation system(DGS), battery systems and loads. The distributed generation systems include combined heat and power(CHP) and small generators such as diesel generators and the renewable energy generators such as photovoltaic(PV) systems, wind power systems. Both of thermal loads and electrical loads are included here as loads. Also the emissions trading scheme to be applied in near future, the cost of unit start-up and the operational characteristics of battery systems are considered as well as the probabilistic characteristics of the renewable energy generation and load. A mathematical equation for optimal operation of this system is modeled based on the mixed integer programming. It is shown that this optimization methodology can be effectively used for economical operation of a microgrid by the case studies.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1966-1967
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• 2007

Photovoltaic(PV) power generation system [1-2] has been extensively studied and watched with keen interest as a clean and renewable power source. So hardware and software studies strongly indicate the feasibility of commercially producing a low cost, user-friendly solar cell curve tracer. Generally, V-I curve tracer indicates only the commonly used solar cell parameters. However, with the conventional V-I curve tracer it is almost impossible to abstract the more detail parameters of solar cell ; A, Rs, and Rsh, which satisfies the user, who aims at the analysis of the development PV power generation system; advanced simulation. In this paper, the proposed method gives us the satisfactory results to abstract the detail parameters of solar cell ; A, Rs, and Rsh

• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.16-21
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• 2011

Since the maximum power operating point(MPOP) of PCS alters with changing atmospheric conditions temperature conditions shadow conditions it is important to operate for PCS to keep maximum power point tracking(MPPT) continuously. This paper presents the results of modeling PV system by PSIM simulator and investigates the influence on the PV system from aspect of power quality i.e. voltage drop. This paper investigates four MPPT algorithms; Perturbation & Observation(P&O) Improved P&O Incremental Conductance(Incond) Differential coefficient method simulated with irradiation temperature change and shadow conditions.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.221-223
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• 2008

This paper presents a maximum power point tracking(MPPT) of Photovoltaic system with chopping ratio of DC-DC converter considered load. A variation of solar irradiation is most important factor in the MPPT of PV system. That is nonlinear, aperiodic and complicated. The paper consists of solar radiation source, DC-DC converter, DC motor and load(cf, pump). NN algorithm apply to DC-DC converter through an adaptive control of neural network, calculates converter-chopping ratio using an adaptive control of NN. The results of an adaptive control of NN compared with the results of converter-chopping ratio which are calculated mathematical modeling and evaluate the proposed algorithm. The experimental data show that an adequacy of the algorithm was established through the compared data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1674-1683
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• 2011

More than 80% of electric loads need DC electricity rather than AC at the moment. If DC power could be supplied directly to the terminal loads, power conversion stages including rectifiers, converters, and power adapters can be reduced or simplified. Therefore, DC microgrids may be able to improve energy efficiency of power distribution systems. In addition, DC microgrids can increase the penetration level of renewable energy resources because many renewable energy resources such as solar photovoltaic(PV) generators, fuel cells, and batteries generate electric power in the form of DC power. The integration of the DC generators to AC electric power systems requires the power conversion circuits that may cause additional energy loss. This paper discusses the capability and feasibility of DC microgrids with regard to energy efficiency analysis through detailed dynamic simulation of DC and AC microgrids. The dynamic simulation models of DC and AC microgrids based on the Microgrid Test System in KEPCO Research Institute are described in detail. Through simulation studies on various conditions, this paper compares the energy efficiency and advantages of DC and AC microgrids.

• Bulletin of the Korea Photovoltaic Society
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• v.6 no.1
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• pp.56-68
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• 2020

Cameroon is a lower middle-income country with a population of 25.87 million inhabitants distributed over a surface area of 475,442 ㎢. Cameroon has very rich potentials in renewable energy resources such as solar energy, wind energy, small hydropower, geothermal energy and biomass. However, renewable energy constitutes less than 0.1% of energy mix of the country. The energy generation mix of Cameroon is dominated by large hydropower and thermal power. Cameroon ratified the Paris Agreement in July 2016 with an ambitious 20% greenhouse gas (GHG) emission reduction. This study attempts to investigate some renewable energy deployment policy-instruments that could enable the country enhance renewable energy deployment, gain energy independence, fulfill Nationally Determined Contribution (NDC) and achieve Sustainable Development Goals. It begins with an analysis of the status of energy sector in Cameroon. It further highlights the importance of renewable energy in mitigating climate change by decarbonizing the energy mix of the country to fulfill NDC and SDGs. Moreover, this study proposes some renewable energy deployment policy-solutions to the government. Solar energy is the most feasible renewable energy source in Cameroon. Feed-in Tariffs (FiT), is the best renewable energy support policy for Cameroon. Finally, this study concludes with some recommendations such as the necessity of building an Energy Storage System as well a renewable energy information and statistics infrastructure.

• Bulletin of the Korea Photovoltaic Society
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• v.3 no.2
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• pp.42-47
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• 2017

The potential induced degradation (PID) phenomenon shows severe power loss within several years from the initial installation of solar power system. The accumulated power loss by PID is inevitable because the PID is suspected only if the power loss exceeds several percent. In this paper, we analyzed the cases of PID diagnosis and recovery by visiting the suspected PID site about 17 months after the installation of the 100kW PV system. The power difference of the two 50kW inverters was more than 20kWh, and the PR difference was more than 8%. From the beginning of the installation, the difference in power gradually increased. The recovery was observed for about 7 months by applying 1000V in the reverse bias at night. As a result, the power difference of the two inverters was recovered to within 2kWh. In the case of a power station suffering from PID in the field, it will be helpful for stable development operation by quick diagnosis and problem solving.