• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.201-203
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• 2002

In recent years there has been a growing interest in renewable energy systems due to the environmental problem and the economic benefits of fuel savings. Such systems are usually connected to the existing power grid for "fuel displacement" purpose as well as of earning some "capacity credit". Wind power generation system(WPGS) is one of the most useful energy resource using natural environment. So far, it was very difficult to simulate the dispersed generation system including WPGS using EMTP or EMTDC because the source of the dispersed generation system has a particular wind power characteristic equation. In this paper, a novel simulation method of WPGS has proposed and a new wind turbine component for EMTDC is also developed. The wind power characteristic equation of wind turbine is used in order to realize the WPGS in EMTDC simulation. And the real field data of weather conditions is interfaced to EMTDC using Fortran program interface method. Consequently the simulation of WPGS using field data is realized in this paper and shows acceptable results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.1
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• pp.25-33
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• 2013

The floating offshore wind turbines are usually exposed to the wave and wind excitations which are irregular and undirected. In this paper, the sloshing characteristics of annular cylindrical tank were experimentally investigated to reduce the structural dynamic motion of floating offshore wind turbine which is robust to the irregular change of excitation direction of wind and wave. The formula for the natural sloshing frequencies of this annular cylindrical tank was derived theoretically. In order to validate this formula, the shaking equipment was established and frequency response functions were measured. Two types of tank were considered. The first and second natural sloshing frequencies were investigated according to the depth of the water. It has been observed that between theoretical and experimental results shows a good agreement.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.236-241
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• 2021

This paper presents a methodology to analyze the interference of maritime traffic control radar by wind turbines installed in the sea, and the interference result of the maritime traffic control radars by a small number of wind turbines installed in sea near Gunsan port (Gunsan vessel traffic services). A ray based electromagnetic analysis software is used to analyze the interference. The geographic information system map containing altitude data, drawing of wind turbines, and sea with waves are imported to the software to analyze the effect of the terrain and the wind turbines. According to the analysis, a small number of wind turbines, not large scale wind farms, has no severe impact on the operation of the radar.

• Journal of Korea Multimedia Society
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• v.25 no.8
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• pp.1097-1108
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• 2022

This paper aimed to design and implement an EMS for real-time power generation control based on wake effect optimization of wind farm, and then to test it in commercial operating wind farm. For real-time control, we proposed the wake band-based optimization and setting the wake effect distance limit, and when the wake effect distance limit was set to 7D in the actual wind farm layout, the calculation time was improved by about 93.94%. In addition, we designed and implemented the script-based EMS for flexible operation logic management in preparation for unexpected issues during testing, and it was installed and tested on a wind farm in commercial operation. However, three issues arose during the testing process. These are the communication interface problem of meteorological tower, the problem of an abnormal wake effect, and the problem of wind turbine yaw control. These issues were solved by modifying the operation logic using EMS's script editor, and the test was successfully completed in the wind farm in commercial operation.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.273-274
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• 2012

This paper investigates control algorithms for a doubly fed induction generator(DFIG) with a back-to-back three-level neutral-point clamped voltage source converter in medium voltage wind power system under unbalanced grid conditions. Two different control algorithms to compensate for unbalanced conditions are proposed. Evaluation factors of control algorithm are fault ride-through(FRT) capability, efficiency, harmonic distortions and torque pulsation. Zero regulated negative sequence stator current control algorithm has the most effective performance concerning FRT capability and efficiency. Ripple-free control algorithm nullifies oscillation component of active power and reactive power. Ripple-free control algorithm shows the least harmonic distortions and torque pulsation. Combination of zero regulated negative sequence stator current and ripple-free control algorithm control algorithm depending on the operating requirements and depth of grid unbalance presents the most optimized performance factors under the generalized unbalanced operating conditions leading to high performance DFIG wind turbine system.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.55.1-55.1
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• 2011

풍력터빈에 적용되는 제어로직에 대한 검증을 실험실 기반에서 검증하기 위해서는 바람 및 터빈에 대한 적절한 모델링이 선행되어야 한다. 특히 피치 및 토크제어에 대한 특성을 검증하기 위해서는 블레이드 공력특성 및 터빈의 동특성에 대한 반영이 필연적이다. 본 논문에서는 풍력터빈 적용 제어로직 검증을 위하여 대상터빈에 대한 스케일링 결과, 바람을 모사하기 위한 구동장치 동작 및 터빈 모사장치에 대한 설계 결과에 대하여 소개하도록 한다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.10
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• pp.528-534
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• 2003

A grid connection algorithm is proposed for the doubly-fed induction generator (DFIG) which is widely adopted in high power variable speed wind turbine. Before the stator of DFIG is connected to grid, rotor-side converter is used to control the induced stator voltage. As a result, the stator transient current is limited below the rate value during the connection by the proposed synchronization of the stator voltage to the grid voltage. A wind power generation simulator using DC motor and wound-rotor induction generator is built and the dynamic characteristics of proposed algorithm is verified experimentally.

• Journal of Power Electronics
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• v.4 no.2
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• pp.65-76
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• 2004

In this paper, the steady-state analysis of the three-phase self-excited induction generator (SEIG) driven by a variable-speed prime mover (VSPM) such as a wind turbine is presented. The steady-state torque-speed characteristics of the VSPM are considered with the three-phase SEIG equivalent circuit for evaluating the operating performances due to the inductive load variations. Furthermore, a PI closed-loop feedback voltage regulation scheme based on the static VAR compensator (SVC) for the three-phase SEIG driven by the VSPM is designed and considered for the wind power generation conditioner. The simulation and experimental results prove the practical effectiveness of the additional SVC with the PI controller-based feedback loop in terms of fast response and high performances.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2000-2001
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• 2007

Wind power generation system based on the PSCAD/EMTD is proposed in this paper for the simulations under the real weather conditions. Real field data of weather condition is interfaced to PSCAD/EMTDC using Fortran program interfaced method. And a new turbine component is developed using characteristic equation of a wind turbine and pitch angle control algorism. The generator output and current supplied into utility can be obtained by the transient analysis using PSCAD/EMTDC.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.9
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• pp.929-936
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• 2015

Nacelle anemometers are mounted on wind-turbine nacelles behind blade roots to measure the free-stream wind speed projected onto the wind turbine for control purposes. However, nacelle anemometers measure the transformed wind speed that is due to the wake effect caused by the blades' rotation and the nacelle geometry, etc. In this paper, we derive the Nacelle Transfer Function (NTF) to calibrate the nacelle wind speed to the free-stream wind speed, as required to carry out the performance test of wind turbines according to the IEC 61400-12-2 Wind-Turbine Standard. For the reference free-stream wind data, we use the Light Detection And Ranging (LiDAR) measurement at the Shinan wind power plant located on the Bigeumdo Island shoreline. To improve the simple linear regression NTF, we derive the multiple nonlinear regression NTF. The standard error of the wind speed was found to have decreased by a factor of 9.4, whereas the mean of the power-output residual distribution decreased by 6.5 when the 2-parameter NTF was used instead of the 1-parameter NTF.