• International Journal of Fluid Machinery and Systems
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• v.2 no.4
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• pp.334-345
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• 2009

Pumped storage power plants are playing a significant role in the contribution to the stabilization of an electrical grid, above all by stable operation and fast reaction to sudden load respectively frequency changes. Optimized efficiency and smooth running characteristics both in pump and turbine operation, improved stability for synchronization in turbine mode, load control in pump mode operation and also short reaction times may be achieved using adjustable speed power units. Such variable speed power plants are applicable for high variations of head (e.g. important for low head pump-turbine projects). Due to the rapid development of power semiconductors and frequency converter technology, feasible solutions can be provided even for large hydro power units. Suitable control strategies as well as clear design criteria contribute significantly to the optimal usage of the pump turbine and motor-generators. The SIMSEN tool for dynamic simulations has been used for comparative investigations of different configurations regarding the power converter topology, types of semiconductors and types of motor-generators including the coupling to the hydraulic system. A brief overview of the advantages & disadvantages of the different solutions can also be found in this paper. Using this approach, a customized solution minimizing cost and exploiting the maximum usage of the pump-turbine unit can be developed in the planning stage of new and modernization pump storage projects.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.236.2-236.2
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• 2010

The tidal current power is the power plant by installing the turbine or rotor where the tidal speed is fast. This system converting the horizontal movement to rotating energy. Tidal power turbine is needed for the dam to utilize the pressure difference. However, tidal current power using the only flow. The tidal current power was evaluated as the impact on the marine environment surrounding was less and the development of eco-friendly way. In this article, we calculated the effect of tidal current turbine on the tidal power generating by mean of CFD. With these calculated results, we checked the possibility of tidal current power using tidal power plant the discharge gate.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.425-432
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• 2019

Molecular dynamics simulations were carried out to analyze the impact on turbine rotational power based on nozzle shapes. y varying two parameters, turbine rotational velocity w and initial velocities ($V_x,V_y$) for generating molecules, turbine rotation velocities of molecules in turbine entrance arc region and turbine exit arc region were calculated. Average momentums were calculated over two regions, respectively and the differences (AMD) were compared and analyzed. The optimal range of w values to enhance AMD was investigated over 4 different nozzle shapes used, and an excellent nozzle shape to achieve more turbine rotational power was drawn.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1897-1904
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• 2008

In this paper, the method for effective stability analysis of Jeju power system in 2011 is proposed. The stability analysis of Jeju power system was carried out by using proposed method In case of Jeju power system with wind turbine generators or without wind turbine generators, including CSC HVDC or VSC HVDC. The steady-state stability is validated by SCR and ESCR, PV curve, QV curve. And the transient stability is analyzed by CCT(Critical Clearing Time). VSC HVDC has more advantages than CSV HVDC on the stability. Also, Jeju power system without wind turbine generators has more advantages than Jeju power system with Wind Turbine Generators on the stability.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.225-228
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• 2012

Thermodynamic and economic analysis on various type of gas turbine combined cycle power plants was presented to build up the criteria for optimization of power plants. The efficiency considered about energy level difference between electricity and heat was introduced. The efficiency on power and heat generation of power plants whose have different purpose was estimated and power generation costs on various type of combined heat and power plants : fired/unfired, condensing/non-condensing mode, single/double pressure HRSG.

• International Journal of Control, Automation, and Systems
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• v.3 no.4
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• pp.533-541
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• 2005

In this paper, a wind turbine with power splitting transmission, which is realized through a novel three-shaft planetary, is presented. The input shaft of the transmission is driven by the rotor of the wind turbine, the output shaft is connected to the grid via the main generator (asynchronous generator), and the third shaft is driven by a control motor with variable speed. The dynamic models of the sub systems of this wind turbine, e.g. the rotor aerodynamics, the drive train dynamics and the power generation unit dynamics, were given and linearized at an operating point. These sub models were integrated in a multidisciplinary dynamic model, which is suitable for control syntheses to optimize the utilization of wind energy and to reduce the excessive dynamic loads. The important dynamic behaviours were investigated and a wind turbine with a soft main shaft was recommend.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.311-315
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• 2012

In these days, promising renewable energy, wind turbine is clean energy but has an environmental pollutant which is noise. Noise assessment is one of the major performance evaluations for wind turbine and nowadays, developing and research for measurement and method of the assessment considering environmental pollutants is being important. Object in this study is that figuring out sound power characteristic of the gearbox for wind turbine through measuring sound intensity. In back-to-back test, we can figure out the noise characteristic of the gearbox for wind turbine through comparing and measuring sound pressure level, sound power level in operating at the each load condition respectively.

• Journal of Power Electronics
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• v.13 no.5
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• pp.854-860
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• 2013

The voltage variation problem at the point of common coupling (PCC) in a grid-connected wind turbine is investigated. The voltage variation problem is one of the most frequent power quality issues for the grid connection of large amounts of input power in a weak grid. Through the simplified modeling of the wind turbine and power network, the magnitude of PCC voltage variation is calculated by using the equivalent circuit parameters and output power of the wind turbine. The required amount of reactive power that can compensate the voltage variation is also presented analytically by using the vector diagram method. The proposed calculation and compensation method of the PCC voltage variation is verified by computer simulations and experiments.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.165.1-165.1
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• 2011

In this paper, it is intended to study about deferences of design and operation properties between large and small hydro-power house's turbine which type is reaction. In generally, turbine of large hydro-power has a more safe and effective energy output mechanisms than small hydro-power's because the turbine of small hydro-power is more sensitive to hydraulic losses. But, it is more effective for the all energy market to improve the capability and efficiency of small hydro-power in the present status of increasing construction of small hydro-power than large hydro-power. Therefore, we intend to investigate and introduce the way to enhance the efficiencies of reaction turbine adopted to small hydro-power.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.310-314
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• 2008

The exploitation of the wind energy resource is a rapidly growing area world-wide. The number of installed units is continuously increasing, and it is important to respect and to deal with the impact of wind turbine. This paper addresses the power quality characteristics of U57 Wind Turbine. 750kW gearless type wind turbine for low wind speed, named U57, is developed by UNISON. The power quality measurement system consists of measuring WTG output current, line-to line voltage and wind speed signal. With using measured data, power quality measurement is evaluated about maximum power, reactive power, voltage fluctuation, harmonics according to IEC 61400-21.