• Title/Summary/Keyword: Photovoltaic Generators

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INTEGRATED SOCIETAL RISK ASSESSMENT FRAMEWORK FOR NUCLEAR POWER AND RENEWABLE ENERGY SOURCES

  • LEE, SANG HUN;KANG, HYUN GOOK
    • Nuclear Engineering and Technology
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    • v.47 no.4
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    • pp.461-471
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    • 2015
  • Recently, the estimation of the social cost of energy sources has been emphasized as various novel energy options become feasible in addition to conventional ones. In particular, the social cost of introducing measures to protect power-distribution systems from power-source instability and the cost of accident-risk response for various power sources must be investigated. To account for these risk factors, an integrated societal risk assessment framework, based on power-uncertainty analysis and accident-consequence analysis, is proposed. In this study, we applied the proposed framework to nuclear power plants, solar photovoltaic systems, and wind-turbine generators. The required capacity of gas-turbine power plants to be used as backup power facilities to compensate for fluctuations in the power output from the main power source was estimated based on the performance indicators of each power source. The average individual health risk per terawatt-hours (TWh) of electricity produced by each power source was quantitatively estimated by assessing accident frequency and the consequences of specific accident scenarios based on the probabilistic risk assessment methodology. This study is expected to provide insight into integrated societal risk analysis, and can be used to estimate the social cost of various power sources.

FPGA-based Centralized Controller for Multiple PV Generators Tied to the DC Bus

  • Ahmed, Ashraf;Ganeshkumar, Pradeep;Park, Joung-Hu;Lee, Hojin
    • Journal of Power Electronics
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    • v.14 no.4
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    • pp.733-741
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    • 2014
  • The integration of photovoltaic (PV) energy sources into DC grid has gained considerable attention because of its enhanced conversion efficiency with reduced number of power conversion stages. During the integration process, a local control unit is normally included with every power conversion stage of the PV source to accomplish the process of maximum power point tracking. A centralized monitoring and supervisory control unit is required for monitoring, power management, and protection of the entire system. Therefore, we propose a field-programmable gate array (FPGA) based centralized control unit that integrates all local controllers with the centralized monitoring unit. The main focus of this study is on the process of integrating many local control units into a single central unit. In this paper, we present design and optimization procedures for the hardware implementation of FPGA architecture. Furthermore, we propose a transient analysis and control design methodology with consideration of the nonlinear characteristics of the PV source. Hardware experiment results verify the efficiency of the central control unit and controller design.

Thermally reused solar energy harvesting using current mirror cells

  • Mostafa Noohi;Ali Mirvakili;Hadi Safdarkhani;Sayed Alireza Sadrossadat
    • ETRI Journal
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    • v.45 no.3
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    • pp.519-533
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    • 2023
  • This paper implements a simultaneous solar and thermal energy harvesting system, as a hybrid energy harvesting (HEH) system, to convert ambient light into electrical energy through photovoltaic (PV) cells and heat absorbed in the body of PV cells. Indeed, a solar panel equipped with serially connected thermoelectric generators not only converts the incoming light into electricity but also takes advantage of heat emanating from the light. In a conventional HEH system, the diode block is used to provide the path for the input source with the highest value. In this scheme, at each time, only one source can be handled to generate its output, while other sources are blocked. To handle this challenge of combining resources in HEH systems, this paper proposes a method for collecting all incoming energies and conveying its summation to the load via the current mirror cells in an approach similar to the maximum power point tracking. This technique is implemented using off-the-shelf components. The measurement results show that the proposed method is a realistic approach for supplying electrical energy to wireless sensor nodes and low-power electronics.

A Study on the PEM Electrolysis Characteristics Using Ti Mesh Coated with Electrocatalysts (Ti Mesh 처리 촉매전극을 이용한 고체고분자 전해질 전기분해 특성연구)

  • Sim, Kyu-Sung;Kim, Youn-Soon;Kim, Jong-Won;Han, Sang-Do
    • Transactions of the Korean hydrogen and new energy society
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    • v.7 no.1
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    • pp.29-37
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    • 1996
  • Alkaline water electrolysis has been commercialized as the only large-scale method for a long time to produce hydrogen and the technology is superior to other methods such as photochemical, thermochemical water splitting, and thermal decomposition method in view of efficiency and related technical problem. However, such conventional electrolyzer do not have high electric efficiency and productivity to apply to large scale hydrogen production for energy or chemical feedstocks. Solid polymer electrolyte water electrolysis using a perfluorocation exchange membrane as an $H^+$ ion conductor is considered to be a promising method, because of capability for operating at high current densities and low cell voltages. So, this is a good technology for the storage of electricity generated by photovoltaic power plants, wind generators and other energy conversion systems. One of the most important R&D topics in electrolyser is how to minimize cell voltage and maximize current density in order to increase the productivity of the electrolyzer. A commercialized technology is the hot press method which the film type electrocatalyst is hot-pressed to soild polymer membrane in order to eliminate the contact resistance. Various technologies, electrocatalyst formed over Nafion membrane surface by means of nonelectrolytic plating process, porous sintered metal(titanium powder) or titanium mesh coated with electrocatalyst, have been studied for preparation of membrane-electrocatalyst composites. In this study some experiments have been conducted at a solid polymer electrolyte water electrolyzer, which consisted of single cell stack with an electrode area of $25cm^2$ in a unipolar arrangement using titanium mesh coated with electrocatalyst.

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Evaluation algorithm for Hosting Capacity of PV System using LDC Method of Step Voltage Regulator in Distribution Systems (배전계통에 있어서 선로전압조정장치의 LDC방식에 의한 태양광전원의 수용성 향상 평가알고리즘)

  • Lee, Se-Yeon;Lee, Hu-Dong;Tae, Dong-Hyun;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.7
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    • pp.20-28
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    • 2020
  • According to the 3020 RE (renewable energy) policy of the Korean Government, distributed generators, including PV (photovoltaic) and WP (wind power) systems, have been installed and operated in distribution systems. On the other hand, if large-scale PV systems are interconnected in a distribution system, the spread of PV systems may be postponed due to a reduction of the hosting capacity in PV systems because of the over-voltage phenomena at the customer end by violating the allowable voltage limits. Under these circumstances, this paper proposes an evaluation algorithm of the hosting capacity of a PV system based on the LDC (line drop compensation) method of SVR (step voltage regulator) to improve the hosting capacity when large-scale PV systems are installed in a distribution system. Moreover, this paper presents a modeling of a complex distribution system, which is composed of a large-scale PV system and SVR with the LDC method using PSCAD/EMTDC. The simulation results confirmed that the proposed algorithm and modeling are useful and practical tools for improving the hosting capacity of a PV system because the customer voltages are maintained within the allowable voltage limits even if 6.5[MW] of the PV system is installed in a distribution system with the LDC method of SVR.