• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.388-389
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• 2013

This paper presents the method for the fluctuation smoothing control by using relaxation time variable control of battery. When the output power of wind farm is changed suddenly, it is necessary to control the output power of wind farm. The smoothing relaxation time is changed within limits of battery output power. Using the hybrid energy storage system (HESS) combined with battery energy storage system and electric double layer capacitor, it is possible to control the output power of wind farm. The capacity of battery is determined by considering the case of the disconnecting wind farm from the grid. To verify the proposed method, simulations are carried out by using PSCAD/EMTDC with actual data of wind farm in the Jeju Island.

• Journal of Environmental Science International
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• v.20 no.7
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• pp.839-843
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• 2011

We have established a wind map of Singapore, a city-state characterized its land cover by urban buildings to confirm a possibility of wind farm development. As a simple but useful approximation of urban canopy, a zero-plane displacement concept was employed. The territory is divided into 15 sectors having similar urban building layouts, and zero-plane displacement, equivalent roughness height at each sector was calculated to setup a terrain boundary condition. Annual mean wind speed and mean wind power density map were drawn by a CFD micrositing model, WindSim where Changi International Airport wind data was used as an in-situ measurement. Unfortunately, predicted wind power density does not exceed 80 $W/m^2$ at 50 m above ground level which would not sufficient for wind power generation. However, the established Singapore wind map is expected to be applied for wind environment assessment and urban planning purpose.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.211-218
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• 2012

Fossil fuel is used all over the world and it produces greenhouse gases due to fossil fuel use. Therefore, it cause global warming and is serious environmental pollution. In order to decrease the environmental pollution, we should use renewable energy which is clean energy. Among several renewable energy, wind energy is the most promising one. Wind power generation is does not produce environmental pollution and could not be exhausted. However, due to wind power generation has irregular power output, it is important to predict generated electrical energy accurately for smoothing wind energy supply. There, we consider use ramp characteristic to forecast accurate wind power output. The ramp increase and decrease rapidly wind power generation during in a short time. Therefore, it can cause problem of unbalanced power supply and demand and get damaged wind turbine. In this paper, we make prediction models using power ramp rate as well as wind speed and wind direction to increase prediction accuracy. Prediction model construction algorithm used multilayer neural network. We built four prediction models with PRR, wind speed, and wind direction and then evaluated performance of prediction models. The predicted values, which is prediction model with all of attribute, is nearly to the observed values. Therefore, if we use PRR attribute, we can increase prediction accuracy of wind power generation.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1397-1405
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• 2017

As the introduction of wind power is steadily increasing, negative effects of wind power become more important. To operate a power system more reliable, the system operator needs to recognize the maximum required capacity of available generators for a certain period. For recognizing the maximum capacity, this paper proposes a methodology to determine an optimal reserve requirement considering wind power, for the certain period in the mid-term perspective. As wind speed is predicted earlier, the difference of the forecasted and the actual wind speed becomes greater. All possible forecast errors should be considered in determining optimal reserve, and they are represented explicitly by the proposed matrix form in this paper. In addition, impacts of the generator failure are also analyzed using the matrix form. Through three main stages which are the scheduling, contingency and evaluation stages, costs associated with power generation, reserve procurement and the usage, and the reliability cost are calculated. The optimal reserve requirement is determined so as to minimize the sum of these costs based on the cost/reliability analysis. In case study, it is performed to analyze the impact of wind power penetration on the reserve requirement, and how major factors affect it.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.3
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• pp.72-77
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• 2014

The cross-section area of cable in the Offshore Wind Farm (OWF) is smaller than that in the onshore wind farm. Because the power loss in OWF is large relatively, the power loss is a key element for the economic evaluation of OWF design. The availability of wind turbine in OWF and the size of OWF are larger than those of onshore wind farm. If the economic evaluation of OWF ignores the availability of wind turbines, the power loss cost of OWF is overpriced. Since there are so many wind turbines, also, the calculation of power loss should be more accurate. In this paper, a method to calculate power loss is proposed for the design of big and complex inner-grid in OWF. The 99.5MW OWF is used for case study to see what effect the proposed method have on the power loss cost.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.7
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• pp.28-37
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• 2015

Owing to the variability of large-scaled wind power system, the development of wind farm management technologies and related compensation methods have been receiving attention. To provide an accurate and reliable output power, certain wind farm adopts a specified management system including a wind prediction model and grid expectation solutions for considering grid condition. Those technologies are focused on improving the reliability and stability issues of wind farms, which can affect not only nearby system devices but also a voltage condition of utility grid. Therefore, to adapt the develop management system, an expectation process about voltage condition of Point of Common Coupling should be integrated in operating system for responding system requirements in real-time basis. This paper introduce a grid imposing method for a real-time based wind farm management system. The expected power can be transferred to the power flow section and the required quantity about reactive power can be calculated through the proposed system. For the verification process, the gauss-seidel method is introduced in the Matlab/Simulink for analysing power flow condition. The entire simulation process was designed to interwork with PSCAD for verifying real power system condition.

• Progress in Superconductivity and Cryogenics
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• v.16 no.4
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• pp.57-61
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• 2014

Output fluctuation which is generated in wind power farm can hinder stability of total power system. The electric energy storage (EES) reduces unstable output, and superconducting magnetic energy storage (SMES) of various EESs has the proper performance for output compensation of wind power farm since it charges and discharges large scale power quickly with high efficiency. However, because of the change of current within SMES, the electromagnetic losses occur in the process of output compensation. In this paper, the thermal effect of the losses that occur in SMES system while compensating in wind power farm is analyzed. The output analysis of wind power farm is processed by numerical analysis, and the losses of SMES system is analyzed by 3D finite element analysis (FEA) simulation tool.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.5
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• pp.554-561
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• 2014

Hybrid wind Diesel stand-alone power systems are considered economically viable and effective to create balance between production and load demand in remote areas where the wind speed is considerable for electric generation, and also, electric energy is not easily available from the grid. In Wind diesel hybrid system, the wind energy system is the main constitute and diesel system forms the back up. This type of hybrid power system saves fuel cost, improves power capacity to meet the increasing demand and maintains the continuity of supply in the system. Problem we face in this system is that even after producing enough power through wind turbine system, considerable portion of this power needs to be dumped due to short term oversupply of power and to maintain the frequency within close tolerances. As a result remaining portion of total energy supplied comes from the diesel generator to overcome the temporal energy shortage. This scenario decreases the overall efficiency of hybrid power system. In this study, efficient Simulink modeling for wind-diesel hybrid system is proposed and some simulations study is carried out to verify the feasibility of the proposed scheme.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1348-1349
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• 2011

In this paper, The case of power performance test for 3MW wind-turbine system is introduced. For the verification of power curve and the certification of wind-turbine, power performance test is very important. This paper described the power testing results of a 3MW wind turbine and analysed an uncertainty about the testing. The measured power curves are very closely coincide with the calculated. Total uncertainty of measured data for Power Curve is 120~200kW in the rated power.

• Journal of Ocean Engineering and Technology
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• v.34 no.6
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• pp.454-460
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• 2020

In 2019, the Korean government announced the 3rd Basic Plan for Energy, which included expanding the rate of renewable energy generation by 30-40% by 2040. Hence, offshore wind power generation, which is relatively easy to construct in large areas, should be considered. The East Sea coast of Korea is a sea area where the depth reaches 50 m, which is deeper than the west coast, even though it is only 2.5 km away from the coastline. Therefore, for offshore wind power projects on the East Sea coast, a floating offshore wind power should be considered instead of a fixed one. In this study, a response analysis was performed by applying the analytical conditions of IEC61400-3-2 for the design of floating offshore wind power generation systems. In the newly revised IEC61400-3-2 international standard, design load cases to be considered in floating offshore wind power systems are specified. The upper structure applied to the numerical analysis was a 5-MW-class wind generator developed by the National Renewable Energy Laboratory (NREL), and the marine environment conditions required for the analysis were based on the Ulsan Meteorological Buoy data from the Korea Meteorological Administration. The FAST v8 developed by NREL was used in the coupled analysis. From the simulation, the maximum response of the six degrees-of-freedom motion and the maximum load response of the joint part were compared. Additionally, redundancy was verified under abnormal conditions. The results indicate that the platform has a maximum displacement radius of approximately 40 m under an extreme sea state, and when one mooring line is broken, this distance increased to approximately 565 m. In conclusion, redundancy should be verified to determine the design of floating offshore wind farms or the arrangement of mooring systems.